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Tag Archives: Output

Java || Snippet – How To Read & Write Data From A File

November 20, 2012 admin No comments

This page will consist of a demonstration of a simple quadratic formula program, which highlights the use of the input/output mechanisms of manipulating a text file. This program will read in data from a file (numbers), manipulate that data, and output new data into a different text file.

REQUIRED KNOWLEDGE FOR THIS SNIPPET

Try/Catch - What Is It? The "Math" Class - sqrt and pow The "Scanner" Class - Used for the input file The "FileWriter" Class - Used for the output file The "File" Class - Used to locate the input/output files Working With Files

NOTE: The data file that is used in this example can be downloaded here.

In order to read in the data .txt file, you need to save the .txt file in the same directory (or folder) as your .java file is saved in. If you are using Eclipse, the default directory will probably be:

Documents > Workspace > [Your project name]

Alternatively, you can execute this command, which will give you the current directory in which your source file resides:

System.out.println(System.getProperty("user.dir"));

Whatever the case, in order to read in the data .txt file, your program must know where it is located on the system.





		
		
			Input/Output Manipulation
			
Java
			
			import java.io.File; // used to locate the input/output files
import java.io.FileWriter; // used for file output
import java.util.Scanner; // used for file input

public class ReadWriteFile
{		
	public static void main(String[] args)
	{
		// declare & initialize variables
		Scanner infile;
		FileWriter outfile;
		double a=0,b=0,c=0;
		double root1=0, root2=0;
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// use a try/catch to check to see if the input file exists, & if not then EXIT
		try
		{
			// this opens the input file
			// YOUR INPUT FILE NAME GOES BELOW 
			infile = new Scanner(new File("INPUT_Quadratic_programmingnotes_freeweq_com.txt"));
			
			// this opens the output file
			// if the file doesnt already exist, it will be created 			
			outfile = new FileWriter(new File("OUTPUT_Quadratic_programmingnotes_freeweq_com.txt"));
			
			// if the file was found, this try/catch will execute, and the loop will 
			// attempt to get the 3 numbers from the input file and place
			// them inside the variables 'a,b,c'
			try
			{
				while(infile.hasNext())
				{
					// this assigns the incoming data to the
					// variables 'a', 'b' and 'c'
					// NOTE: it is just like a normal scanner statement 				
					a = infile.nextInt();
					b = infile.nextInt();
					c = infile.nextInt();
					
					// NOTE: if you want to read in data into an array
					// your declaration would be like this
					// ------------------------------------
					// a[counter] = infile.nextInt(); 
					// b[counter] = infile.nextInt(); 
					// c[counter] = infile.nextInt();
					// ++counter; 				
				}
			}
			catch(Exception e) 
			{
				// if there was an error on input, (i.e the input file contains letters) 
				// this block will execite, and the program will exit
				System.err.println("There is a formatting error in the input file!n" +
						"The input file should contain only 3 numbersn");
				System.exit(1);
			}
			
			// this does the quadratic formula calculations
			root1 = ((-b) + Math.sqrt(Math.pow(b,2) - (4*a*c)))/(2*a);
			root2 = ((-b) - Math.sqrt(Math.pow(b,2) - (4*a*c)))/(2*a); 
			
			// this displays the numbers to screen via stdout
			System.out.println("For the numbers:na = "+a+"nb = "+b+"nc = "+c);
			System.out.println("nroot 1 = "+root1+"nroot 2 = "+root2); 	
			
			// this saves the data to the output file
			// NOTE: its almost exactly the same as the above print statement, except
			// the 'write' function is dependent on the "newline" (NL) method 
			// to generate a line break
			String NL = System.getProperty("line.separator"); 
			outfile.write("For the numbers:"+NL+"a = "+a+NL+"b = "+b+NL+"c = "+c);
			outfile.write(NL+NL+"root 1 = "+root1+NL+"root 2 = "+root2); 
			
			// close the input/output files once you are done using them
			infile.close();
			outfile.close();
		}
		catch(Exception e) 
		{
			// if the file cannot be found, this block will execute, and the
			// program will exit
			System.err.println("Error, the input file could not be found!n"
					+e.getMessage());
			System.exit(1);
		}
		System.out.println("nProgram Success!!n");		
	}// end of main	
}// http://programmingnotes.org/
			
				
					
				
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						import java.io.File; // used to locate the input/output files
import java.io.FileWriter; // used for file output
import java.util.Scanner; // used for file input
 
public class ReadWriteFile
{		
	public static void main(String[] args)
	{
		// declare & initialize variables
		Scanner infile;
		FileWriter outfile;
		double a=0,b=0,c=0;
		double root1=0, root2=0;
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// use a try/catch to check to see if the input file exists, & if not then EXIT
		try
		{
			// this opens the input file
			// YOUR INPUT FILE NAME GOES BELOW 
			infile = new Scanner(new File("INPUT_Quadratic_programmingnotes_freeweq_com.txt"));
			
			// this opens the output file
			// if the file doesnt already exist, it will be created 			
			outfile = new FileWriter(new File("OUTPUT_Quadratic_programmingnotes_freeweq_com.txt"));
			
			// if the file was found, this try/catch will execute, and the loop will 
			// attempt to get the 3 numbers from the input file and place
			// them inside the variables 'a,b,c'
			try
			{
				while(infile.hasNext())
				{
					// this assigns the incoming data to the
					// variables 'a', 'b' and 'c'
					// NOTE: it is just like a normal scanner statement 				
					a = infile.nextInt();
					b = infile.nextInt();
					c = infile.nextInt();
					
					// NOTE: if you want to read in data into an array
					// your declaration would be like this
					// ------------------------------------
					// a[counter] = infile.nextInt(); 
					// b[counter] = infile.nextInt(); 
					// c[counter] = infile.nextInt();
					// ++counter; 				
				}
			}
			catch(Exception e) 
			{
				// if there was an error on input, (i.e the input file contains letters) 
				// this block will execite, and the program will exit
				System.err.println("There is a formatting error in the input file!n" +
						"The input file should contain only 3 numbersn");
				System.exit(1);
			}
			
			// this does the quadratic formula calculations
			root1 = ((-b) + Math.sqrt(Math.pow(b,2) - (4*a*c)))/(2*a);
			root2 = ((-b) - Math.sqrt(Math.pow(b,2) - (4*a*c)))/(2*a); 
			
			// this displays the numbers to screen via stdout
			System.out.println("For the numbers:na = "+a+"nb = "+b+"nc = "+c);
			System.out.println("nroot 1 = "+root1+"nroot 2 = "+root2); 	
			
			// this saves the data to the output file
			// NOTE: its almost exactly the same as the above print statement, except
			// the 'write' function is dependent on the "newline" (NL) method 
			// to generate a line break
			String NL = System.getProperty("line.separator"); 
			outfile.write("For the numbers:"+NL+"a = "+a+NL+"b = "+b+NL+"c = "+c);
			outfile.write(NL+NL+"root 1 = "+root1+NL+"root 2 = "+root2); 
			
			// close the input/output files once you are done using them
			infile.close();
			outfile.close();
		}
		catch(Exception e) 
		{
			// if the file cannot be found, this block will execute, and the
			// program will exit
			System.err.println("Error, the input file could not be found!n"
					+e.getMessage());
			System.exit(1);
		}
		System.out.println("nProgram Success!!n");		
	}// end of main	
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output
(Remember to include the example input file)

Welcome to My Programming Notes' Java Program.
For the numbers: a = 2.0 b = 4.0 c = -16.0 root 1 = 2.0 root 2 = -4.0
Program Success!!

C++ || Snippet – How To Swap Two Numbers Without Using A Third “Temporary” Variable

July 23, 2012 admin No comments

The following are three programs which demonstrates how to swap two numbers without using a third “temporary” variable.

Why would anyone want to swap two numbers without utilizing a third variable? There is no real reason to do so other than the fact that exercises such as these are typically used as programming assignments/interview questions. This is a technique that’s rarely ever practical in a real world setting, but it is still an interesting task nonetheless.





		
		
			#1 - Using Simple Math
			
C++
			
			#include <iostream>
using namespace std;

int main() 
{
	// declare variables
	int x = 0;
	int y = 0;

	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;

	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using simple math
	x = x+y;
	y = x-y;
	x = x-y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
using namespace std;
 
int main() 
{
	// declare variables
	int x = 0;
	int y = 0;
 
	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
 
	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using simple math
	x = x+y;
	y = x-y;
	x = x-y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/

SAMPLE OUTPUT:

Please enter two numbers: 7 28
Item #1 = 7 Item #2 = 28 Switching the numbers..
Item #1 = 28 Item #2 = 7





		
		
			#2 - Using The XOR Swap Algorithm
			
C++
			
			#include <iostream>
using namespace std;

int main() 
{
	// declare variables
	int x = 0;
	int y = 0;

	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;

	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using the xor swap algorithm
	x ^= y;
	y ^= x;
	x ^= y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
using namespace std;
 
int main() 
{
	// declare variables
	int x = 0;
	int y = 0;
 
	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
 
	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using the xor swap algorithm
	x ^= y;
	y ^= x;
	x ^= y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/

SAMPLE OUTPUT:

Please enter two numbers: 5 12453
Item #1 = 5 Item #2 = 12453 Switching the numbers..
Item #1 = 12453 Item #2 = 5





		
		
			#3 - Using The In-Built Swap Function
			
C++
			
			#include <iostream>
#include <algorithm>
using namespace std;

int main() 
{
	// declare variables
	int x = 0;
	int y = 0;

	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;

	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using the in-built swap function
	swap(x, y);

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
#include <algorithm>
using namespace std;
 
int main() 
{
	// declare variables
	int x = 0;
	int y = 0;
 
	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
 
	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using the in-built swap function
	swap(x, y);
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/

SAMPLE OUTPUT:

Please enter two numbers: 2132 6547546
Item #1 = 2132 Item #2 = 6547546 Switching the numbers..
Item #1 = 6547546 Item #2 = 2132

Assembly || How To Obtain & Display Integer Data

July 12, 2012 admin No comments

Displaying text to the screen was discussed in the previous article, and this page will be more of the same. Utilizing the printf and scanf functions which are available in C, this page will demonstrate how to obtain and display integer data; and more importantly, demonstrate how to store a 64-bit integer into an assembly program.

==== Obtain & Display Integer Data ====

Here is our driver.c file, which starts things off.





		
		
			#1 - driver.c -- This Starts Things Off
			
C
			
			// ==========================================================================================================
//	Author: K Perkins
//	Date:   Jul 12, 2012
//	Program: Display A Number
//	Taken From: http://programmingnotes.org/
//	File:  driver.c
//
// Purpose: This is the driver to the "Display A Number" program. Driver.c only calls displayNum.asm. This 
//  file is used just as a "driver" and demostrates how to use a C file along with an Assembly file to 
//  create one working program. Once the Assembly file finishes, control of the program is then passed back 
//  to the driver.c file, then the program closes
//
//              ----- These are the commands to link all the files together -------
//
// (1) Compile driver.c file:                 gcc -c -Wall -m64 -std=c99 -l driver.lis -o driver.o driver.c
// (2) displayNum.asm assembler file:         nasm -f elf64 -l displayNum.lis -o displayNum.o displayNum.asm
// (3) Link all files:                        gcc -m64 -o displayNum.out driver.o displayNum.o
// (4) Execute in 64-bit protected mode:     ./displayNum.out
//
// ===== Begin code area ====================================================================================
#include <stdio.h> 

// external function prototype
extern unsigned long int DisplayNum();

int main()
{
    // declare variable
    unsigned long int returnCode = 1987;
    
    // display message to the screen
    printf("nnWelcome to My Programming Notes' Assembly Program.n");
    
    printf("nControl will now be passed to the Assembly file...nn");
        
    // here is a function call to the assembly file, where the asm file passes
    // back a return code to this current file, which will be displayed below
    returnCode = DisplayNum();
    
    printf("nControl has now been passed back from the Assembly file to the C file!n");
    printf("nThe return code is: %lu", returnCode);
    printf("nnBYE!n");  
     
    return returnCode;
}// http://programmingnotes.org/
			
				
					
				
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						// ==========================================================================================================
//	Author: K Perkins
//	Date:   Jul 12, 2012
//	Program: Display A Number
//	Taken From: http://programmingnotes.org/
//	File:  driver.c
//
// Purpose: This is the driver to the "Display A Number" program. Driver.c only calls displayNum.asm. This 
//  file is used just as a "driver" and demostrates how to use a C file along with an Assembly file to 
//  create one working program. Once the Assembly file finishes, control of the program is then passed back 
//  to the driver.c file, then the program closes
//
//              ----- These are the commands to link all the files together -------
//
// (1) Compile driver.c file:                 gcc -c -Wall -m64 -std=c99 -l driver.lis -o driver.o driver.c
// (2) displayNum.asm assembler file:         nasm -f elf64 -l displayNum.lis -o displayNum.o displayNum.asm
// (3) Link all files:                        gcc -m64 -o displayNum.out driver.o displayNum.o
// (4) Execute in 64-bit protected mode:     ./displayNum.out
//
// ===== Begin code area ====================================================================================
#include <stdio.h> 
 
// external function prototype
extern unsigned long int DisplayNum();
 
int main()
{
    // declare variable
    unsigned long int returnCode = 1987;
    
    // display message to the screen
    printf("nnWelcome to My Programming Notes' Assembly Program.n");
    
    printf("nControl will now be passed to the Assembly file...nn");
        
    // here is a function call to the assembly file, where the asm file passes
    // back a return code to this current file, which will be displayed below
    returnCode = DisplayNum();
    
    printf("nControl has now been passed back from the Assembly file to the C file!n");
    printf("nThe return code is: %lu", returnCode);
    printf("nnBYE!n");  
     
    return returnCode;
}// http://programmingnotes.org/

The “driver” file really only has one task, and that is simply to call the assembly function named ‘DisplayNum()’ as noted on line 38. This is a routine that is present among all the code on this site. Click here for an explanation on why a “driver” is used.

And here is the assembly file.





		
		
			#2 - displayNum.asm -- Display A Number
			
Assembly (x86)
			
			;================================================================================================================
;	Author: K Perkins
;	Date:   Jul 12, 2012
;	Program: Display A Number
;	Taken From: http://programmingnotes.org/
;	File:  displayNum.asm
;
; Purpose: This is the displayNum.asm file which demonstrates how to obtain & display numbers to
;   the screen in assembly using C functions.
;
;===== Begin code area ========================================================================================== 
extern printf                                     ;External functions printf & scanf 
extern scanf                                      ;taken from the C library which will be 
                                                  ;used for user input/output to the screen
;
segment .data                                     ;Place initialized data here
;
;======== Text declarations & variables which will be displayed to the user =====================================
       getNumber                     db "Please enter a number: ",0
       displayNumber                 db "The number you just entered is: ", 0
       unsignedLongIntegerInput      db "%lu", 0
       stringDataOutput              db "%s", 0
       newLine                       db 10, 0 
       displayLineSeperator          db "--------------------------------------------",10,0       
;       
;;========= End of text declarations which will be displayed to the user ========================================
;
segment .bss                                      ;Place un-initialized data here
;
myInt    resq      1                              ;Pointer for use by scanf to store a number from the user
;
segment .text                                     ;Place instruction code here
;
global DisplayNum                                 ;DisplayNum- the declarationthat is visible 
                                                  ;for other programs to link to it
;                                                  
DisplayNum:                                       ;This is an entry point. Execution will begin here.
;
;============= Push registers to the stack ======================================================================
;safe programming which pushes all registers to the stack so data doesnt get corrupted
push rbp
push rbx
push rcx
push rdx
push rdi                                                  
push rsi 
push rbp                                                   
push r8                                                    
push r9
push r10
push r11
push r12
push r13
push r14
push r15
;
;================ End of Push Registers =========================================================================
;
; Left side: X86 instructions                     ;Right side: the narrative 'A.K.A'the story about this program.
;
;===== #1 Display Line Seperator ================================================================================
       mov qword rdi, stringDataOutput            ;Prepare printf for string output
       mov qword rsi, displayLineSeperator        ;The 'line seperator' is displayed
       mov qword rax, 0                           ;No vector registers used    
       call      printf                           ;printf is going to output the data         
;
;===== #2 Prompt The User For Integer Input =====================================================================
       mov qword rdi, stringDataOutput            ;Prepare printf for string output
       mov qword rsi, getNumber                   ;A Prompt to enter in a number will be displayed 
       mov qword rax, 0                           ;No vector registers used
       call      printf                           ;printf is going to output the data        
;
;===== #3 This Obtains User Input Using Scanf ===================================================================
       mov qword rdi, unsignedLongIntegerInput    ;Prepare scanf to get one 64-bit integer
       mov qword rsi, myInt                       ;Set up indirect addressing for scanf
       mov qword rax, 0                           ;No vector registers used.
       call      scanf                            ;The unsigned long integer is placed into 'myInt'
;
;===== #4 Prompt The User That An Integer Will Be Displayed =====================================================
       mov qword rdi, stringDataOutput            ;Prepare printf for string output
       mov qword rsi, displayNumber               ;A Prompt to display the number will be displayed 
       mov qword rax, 0                           ;No vector registers used
       call      printf                           ;printf is going to output the data  
;
;===== #5 Display The Number To User ============================================================================
       mov qword rdi, unsignedLongIntegerInput    ;Prepare printf to output one 64-bit integer
       mov qword rsi, [myInt]                     ;'myInt' will be passed to printf
       mov qword rax, 0                           ;No vector registers used.
       call      printf                           ;printf is going to output the data
;
;===== #6 This Prints A Newline =================================================================================
       mov qword rdi, stringDataOutput            ;Prepare printf to make string output
       mov qword rsi, newLine                     ;The newline character ascii code is passed to printf
       mov qword rax, 0                           ;No vector registers used.
       call      printf                           ;printf is going to output the data
;       
;===== #7 Display Line Seperator ================================================================================
       mov qword rdi, stringDataOutput            ;Prepare printf for string output
       mov qword rsi, displayLineSeperator        ;The 'line seperator' is displayed
       mov qword rax, 0                           ;No vector registers used    
       call      printf                           ;printf is going to output the data                
;
; END CODE EXECUTION FOR DISPLAYNUM.ASM
;
;====== pop the registers back from the in reverse order stack ==================================================
pop r15
pop r14
pop r13
pop r12
pop r11
pop r10
pop r9
pop r8
pop rbp
pop rsi
pop rdi
pop rdx
pop rcx
pop rbx
pop rbp
;
;===== END - RETURN TO CALLED FUNCTION ==========================================================================
       mov       rax, 0                           ;return 0 to the called function
       ret                                        ;ret pops the stack taking away 8 bytes
; 
; http://programmingnotes.org/
;      
;===== End of DisplayNum subprogram =============================================================================
			
				
					
				
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						;================================================================================================================
;	Author: K Perkins
;	Date:   Jul 12, 2012
;	Program: Display A Number
;	Taken From: http://programmingnotes.org/
;	File:  displayNum.asm
;
; Purpose: This is the displayNum.asm file which demonstrates how to obtain & display numbers to
;   the screen in assembly using C functions.
;
;===== Begin code area ========================================================================================== 
extern printf                                     ;External functions printf & scanf 
extern scanf                                      ;taken from the C library which will be 
                                                  ;used for user input/output to the screen
;
segment .data                                     ;Place initialized data here
;
;======== Text declarations & variables which will be displayed to the user =====================================
       getNumber                     db "Please enter a number: ",0
       displayNumber                 db "The number you just entered is: ", 0
       unsignedLongIntegerInput      db "%lu", 0
       stringDataOutput              db "%s", 0
       newLine                       db 10, 0 
       displayLineSeperator          db "--------------------------------------------",10,0       
;       
;;========= End of text declarations which will be displayed to the user ========================================
;
segment .bss                                      ;Place un-initialized data here
;
myInt    resq      1                              ;Pointer for use by scanf to store a number from the user
;
segment .text                                     ;Place instruction code here
;
global DisplayNum                                 ;DisplayNum- the declarationthat is visible 
                                                  ;for other programs to link to it
;                                                  
DisplayNum:                                       ;This is an entry point. Execution will begin here.
;
;============= Push registers to the stack ======================================================================
;safe programming which pushes all registers to the stack so data doesnt get corrupted
push rbp
push rbx
push rcx
push rdx
push rdi                                                  
push rsi 
push rbp                                                   
push r8                                                    
push r9
push r10
push r11
push r12
push r13
push r14
push r15
;
;================ End of Push Registers =========================================================================
;
; Left side: X86 instructions                     ;Right side: the narrative 'A.K.A'the story about this program.
;
;===== #1 Display Line Seperator ================================================================================
       mov qword rdi, stringDataOutput            ;Prepare printf for string output
       mov qword rsi, displayLineSeperator        ;The 'line seperator' is displayed
       mov qword rax, 0                           ;No vector registers used    
       call      printf                           ;printf is going to output the data         
;
;===== #2 Prompt The User For Integer Input =====================================================================
       mov qword rdi, stringDataOutput            ;Prepare printf for string output
       mov qword rsi, getNumber                   ;A Prompt to enter in a number will be displayed 
       mov qword rax, 0                           ;No vector registers used
       call      printf                           ;printf is going to output the data        
;
;===== #3 This Obtains User Input Using Scanf ===================================================================
       mov qword rdi, unsignedLongIntegerInput    ;Prepare scanf to get one 64-bit integer
       mov qword rsi, myInt                       ;Set up indirect addressing for scanf
       mov qword rax, 0                           ;No vector registers used.
       call      scanf                            ;The unsigned long integer is placed into 'myInt'
;
;===== #4 Prompt The User That An Integer Will Be Displayed =====================================================
       mov qword rdi, stringDataOutput            ;Prepare printf for string output
       mov qword rsi, displayNumber               ;A Prompt to display the number will be displayed 
       mov qword rax, 0                           ;No vector registers used
       call      printf                           ;printf is going to output the data  
;
;===== #5 Display The Number To User ============================================================================
       mov qword rdi, unsignedLongIntegerInput    ;Prepare printf to output one 64-bit integer
       mov qword rsi, [myInt]                     ;'myInt' will be passed to printf
       mov qword rax, 0                           ;No vector registers used.
       call      printf                           ;printf is going to output the data
;
;===== #6 This Prints A Newline =================================================================================
       mov qword rdi, stringDataOutput            ;Prepare printf to make string output
       mov qword rsi, newLine                     ;The newline character ascii code is passed to printf
       mov qword rax, 0                           ;No vector registers used.
       call      printf                           ;printf is going to output the data
;       
;===== #7 Display Line Seperator ================================================================================
       mov qword rdi, stringDataOutput            ;Prepare printf for string output
       mov qword rsi, displayLineSeperator        ;The 'line seperator' is displayed
       mov qword rax, 0                           ;No vector registers used    
       call      printf                           ;printf is going to output the data                
;
; END CODE EXECUTION FOR DISPLAYNUM.ASM
;
;====== pop the registers back from the in reverse order stack ==================================================
pop r15
pop r14
pop r13
pop r12
pop r11
pop r10
pop r9
pop r8
pop rbp
pop rsi
pop rdi
pop rdx
pop rcx
pop rbx
pop rbp
;
;===== END - RETURN TO CALLED FUNCTION ==========================================================================
       mov       rax, 0                           ;return 0 to the called function
       ret                                        ;ret pops the stack taking away 8 bytes
; 
; http://programmingnotes.org/
;      
;===== End of DisplayNum subprogram =============================================================================

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The text declarations highlighted under the segment .data section are important, particularly the variable named “unsignedLongIntegerInput.” That variable is used to obtain data from the user, as noted on line 74-77. Note, that this same variable is also used to display the integer data back to the user, which is also displayed on lines 86-89.

The rest of the code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

After you assemble the above code (see below), you should get this as your output:

Welcome to My Programming Notes' Assembly Program.
Control will now be passed to the Assembly file... -------------------------------------------- Please enter a number: 1858 The number you just entered is: 1858 -------------------------------------------- Control has now been passed back from the Assembly file to the C file! The return code is: 0
BYE!

==== ASSEMBLING THE CODE ====

This can be achieved by simply opening the teminal, and doing a copy/paste of the commands listed on the ‘driver.c’ file, lines 15 thru 18. Make sure to compile them in order for the sake of continuity.





		
		
			 (1) Compile driver.c file:                 gcc -c -Wall -m64 -std=c99 -l driver.lis -o driver.o driver.c
 (2) displayNum.asm assembler file:         nasm -f elf64 -l displayNum.lis -o displayNum.o displayNum.asm
 (3) Link all files:                        gcc -m64 -o displayNum.out driver.o displayNum.o
 (4) Execute in 64-bit protected mode:     ./displayNum.out
			
				
					
				
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						 (1) Compile driver.c file:                 gcc -c -Wall -m64 -std=c99 -l driver.lis -o driver.o driver.c
 (2) displayNum.asm assembler file:         nasm -f elf64 -l displayNum.lis -o displayNum.o displayNum.asm
 (3) Link all files:                        gcc -m64 -o displayNum.out driver.o displayNum.o
 (4) Execute in 64-bit protected mode:     ./displayNum.out

Be advised, that the commands to assemble the code is designed to run in 64-bit mode. If you are not running a 64-bit machine, the commands will most likely fail to assemble.

If you are running a Windows computer and would like to assemble the code, look here or here for information.

You will need to change the 64-bit registers to 32-bit registers in the “displayNum.asm” file, aswell as removing lines 41-55 and lines 106-120 respectively in order to run the program successfully.

Assembly || Hello World!

July 09, 2012 admin No comments

This page will consist of creating the typical “hello world!” application. if you have never programmed in assembly before, this will be very interesting as the syntax is very different from most high level programming languages.

As noted on the introductory page, the assembly code presented on this site (X86-64) was assembled using The Netwide Assembler (NASM) under the Unix platform (Ubuntu) in association with C/C++ files. The purpose of combining Assembly code in association with C/C++ files is to demonstrate how each language “talks” to each other. Also, more importantly it is because today, it is unusual to create a stand alone program written completely in assembly language. Why is that the case? Because It is much easier and faster to program in a high level language than it is in assembly. So why should you learn assembly? Learning assembly can be most useful to help one gain a deeper understanding of how computers work, aswell as helping one to better understand how compilers and higher level languages like C work.

==== HELLO WORLD ====

All of the programs presented on this site will start with a simple C or C++ driver program like so:





		
		
			#1 - driver.c -- This Starts Things Off
			
C
			
			// ===================================================================================
//	Author: K Perkins
//	Date:   Jul 9, 2012
//	Program: Hello World
//	Taken From: http://programmingnotes.org/
//	File:  driver.c
//
// Purpose: This is the driver to the Hello World program. Driver.c only calls 
//  helloWorld.asm. This file is used just as a "driver" and demostrates how to use a 
//  C file along with an Assembly file to create one working program. Once the Assembly
//  file displays "Hello World" to the screen, control of the program is passed 
//  back to the driver.c file, then the program closes
//
//              ----- These are the commands to link all the files together -------
//
// (1) Compile driver.c file:                 gcc -c -Wall -m64 -std=c99 -l driver.lis -o driver.o driver.c
// (2) helloWorld.asm assembler file	      nasm -f elf64 -l helloWorld.lis -o helloWorld.o helloWorld.asm
// (3) Link all files:                        gcc -m64 -o helloWorld.out driver.o helloWorld.o
// (4) Execute in 64-bit protected mode:     ./helloWorld.out
//
// ===== Begin code area ==============================================================
#include <stdio.h> 

// external function prototype
extern unsigned long int DisplayHelloWorld();

int main()
{
    // declare variable
    unsigned long int returnCode = 1987;
    
    // display message to the screen
    printf("nnWelcome to My Programming Notes' Assembly Program.n");
    
    printf("nControl will now be passed to the Assembly file...nn");
        
    // here is a function call to the assembly file, where the asm file passes
    // back a return code to this current file, which will be displayed below
    returnCode = DisplayHelloWorld();
    
    printf("nControl has now been passed back from the Assembly file to the C file!n");
    printf("nThe return code is: %lu", returnCode);
    printf("nnBYE!n");  
     
    return returnCode;
}// http://programmingnotes.org/
			
				
					
				
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						// ===================================================================================
//	Author: K Perkins
//	Date:   Jul 9, 2012
//	Program: Hello World
//	Taken From: http://programmingnotes.org/
//	File:  driver.c
//
// Purpose: This is the driver to the Hello World program. Driver.c only calls 
//  helloWorld.asm. This file is used just as a "driver" and demostrates how to use a 
//  C file along with an Assembly file to create one working program. Once the Assembly
//  file displays "Hello World" to the screen, control of the program is passed 
//  back to the driver.c file, then the program closes
//
//              ----- These are the commands to link all the files together -------
//
// (1) Compile driver.c file:                 gcc -c -Wall -m64 -std=c99 -l driver.lis -o driver.o driver.c
// (2) helloWorld.asm assembler file	      nasm -f elf64 -l helloWorld.lis -o helloWorld.o helloWorld.asm
// (3) Link all files:                        gcc -m64 -o helloWorld.out driver.o helloWorld.o
// (4) Execute in 64-bit protected mode:     ./helloWorld.out
//
// ===== Begin code area ==============================================================
#include <stdio.h> 
 
// external function prototype
extern unsigned long int DisplayHelloWorld();
 
int main()
{
    // declare variable
    unsigned long int returnCode = 1987;
    
    // display message to the screen
    printf("nnWelcome to My Programming Notes' Assembly Program.n");
    
    printf("nControl will now be passed to the Assembly file...nn");
        
    // here is a function call to the assembly file, where the asm file passes
    // back a return code to this current file, which will be displayed below
    returnCode = DisplayHelloWorld();
    
    printf("nControl has now been passed back from the Assembly file to the C file!n");
    printf("nThe return code is: %lu", returnCode);
    printf("nnBYE!n");  
     
    return returnCode;
}// http://programmingnotes.org/

The “driver” file really only has one task, and that is simply to call the assembly function named ‘DisplayHelloWorld()’ as noted on line 39. This is a routine that will be present among all the code on this site.

There are several advantages in using the C driver routine. First, this lets the C system set up the program to run correctly in protected mode. All the segments and their corresponding segment registers will be initialized by C. The assembly code doesn’t need to worry about any of this. Secondly, the C library will also be available to be used by the assembly code.

The following shows a simple assembly program utilizing the C function “printf” to display ‘Hello World’ to the screen.





		
		
			#2 - helloWorld.asm -- Display Hello World
			
Assembly (x86)
			
			;=====================================================================================
;	Author: K Perkins
;	Date:   Jul 9, 2012
;	Program: Hello World
;	Taken From: http://programmingnotes.org/
;	File:  helloWorld.asm
;
; Purpose: This is the helloWorld.asm file which demonstrates how to display text to
;   the screen in assembly using C libraries.
;
;===== Begin code area =============================================================== 
extern printf                                     ;External function printf taken 
                                                  ;from the  C library which will be 
                                                  ;used to display output to the screen
;
segment .data                                     ;Place initialized data here
;
;======== Text declarations & variables which will be displayed to the user ==========
       displayMessage           db "Hello World!",10, 0
       specifierForStringData   db "%s", 0 
       displayLineSeperator     db "--------------------------------------------",10,0       
;       
;;========= End of text declarations which will be displayed to the user =============
;
segment .bss                                      ;Place un-initialized data here
;
segment .text                                     ;Place instruction code here
;
global DisplayHelloWorld                          ;DisplayHelloWorld- the declaration 
                                                  ;that is visible for other programs 
                                                  ;to link to it
;                                                  
DisplayHelloWorld:                                ;This is an entry point. Execution 
                                                  ;will begin here.
;
;============= Push registers to the stack ===========================================
;safe programming which pushes all registers to the stack so data doesnt get corrupted
push rbp
push rbx
push rcx
push rdx
push rdi                                                  
push rsi 
push rbp                                                   
push r8                                                    
push r9
push r10
push r11
push r12
push r13
push r14
push r15
;
;================ End of Push Registers ==============================================
;
; Left side: X86 instructions                     ;Right side: the narrative 'A.K.A' 
                                                  ;the story about this program.
;
;===== #1 Display Line Seperator =====================================================
       mov qword rdi, specifierForStringData      ;Prepare printf for string output
       mov qword rsi, displayLineSeperator        ;The 'line seperator' is displayed
       mov qword rax, 0                           ;No vector registers used    
       call      printf                           ;printf is going to output the data         
;
;===== #2 Display Hello World ========================================================
       mov qword rdi, specifierForStringData      ;Prepare printf for string output
       mov qword rsi, displayMessage              ;Hello World will be displayed
       mov qword rax, 0                           ;No vector registers used
       call      printf                           ;printf is going to output the  data        
;
;===== #3 Display Line Seperator =====================================================
       mov qword rdi, specifierForStringData      ;Prepare printf for string output
       mov qword rsi, displayLineSeperator        ;The 'line seperator' is displayed
       mov qword rax, 0                           ;No vector registers used    
       call      printf                           ;printf is going to output the data             
;
; END CODE EXECUTION FOR HELLOWORLD.ASM
;
;====== pop the registers back from the stack in reverse order ========================
pop r15
pop r14
pop r13
pop r12
pop r11
pop r10
pop r9
pop r8
pop rbp
pop rsi
pop rdi
pop rdx
pop rcx
pop rbx
pop rbp
;
;===== END - RETURN TO CALLED FUNCTION ===============================================
       mov       rax, 0                           ;return 0 to the called function
       ret                                        ;ret pops the stack taking away 8 bytes
; 
; http://programmingnotes.org/
;      
;===== End of DisplayHelloWorld subprogram ===========================================
			
				
					
				
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						;=====================================================================================
;	Author: K Perkins
;	Date:   Jul 9, 2012
;	Program: Hello World
;	Taken From: http://programmingnotes.org/
;	File:  helloWorld.asm
;
; Purpose: This is the helloWorld.asm file which demonstrates how to display text to
;   the screen in assembly using C libraries.
;
;===== Begin code area =============================================================== 
extern printf                                     ;External function printf taken 
                                                  ;from the  C library which will be 
                                                  ;used to display output to the screen
;
segment .data                                     ;Place initialized data here
;
;======== Text declarations & variables which will be displayed to the user ==========
       displayMessage           db "Hello World!",10, 0
       specifierForStringData   db "%s", 0 
       displayLineSeperator     db "--------------------------------------------",10,0       
;       
;;========= End of text declarations which will be displayed to the user =============
;
segment .bss                                      ;Place un-initialized data here
;
segment .text                                     ;Place instruction code here
;
global DisplayHelloWorld                          ;DisplayHelloWorld- the declaration 
                                                  ;that is visible for other programs 
                                                  ;to link to it
;                                                  
DisplayHelloWorld:                                ;This is an entry point. Execution 
                                                  ;will begin here.
;
;============= Push registers to the stack ===========================================
;safe programming which pushes all registers to the stack so data doesnt get corrupted
push rbp
push rbx
push rcx
push rdx
push rdi                                                  
push rsi 
push rbp                                                   
push r8                                                    
push r9
push r10
push r11
push r12
push r13
push r14
push r15
;
;================ End of Push Registers ==============================================
;
; Left side: X86 instructions                     ;Right side: the narrative 'A.K.A' 
                                                  ;the story about this program.
;
;===== #1 Display Line Seperator =====================================================
       mov qword rdi, specifierForStringData      ;Prepare printf for string output
       mov qword rsi, displayLineSeperator        ;The 'line seperator' is displayed
       mov qword rax, 0                           ;No vector registers used    
       call      printf                           ;printf is going to output the data         
;
;===== #2 Display Hello World ========================================================
       mov qword rdi, specifierForStringData      ;Prepare printf for string output
       mov qword rsi, displayMessage              ;Hello World will be displayed
       mov qword rax, 0                           ;No vector registers used
       call      printf                           ;printf is going to output the  data        
;
;===== #3 Display Line Seperator =====================================================
       mov qword rdi, specifierForStringData      ;Prepare printf for string output
       mov qword rsi, displayLineSeperator        ;The 'line seperator' is displayed
       mov qword rax, 0                           ;No vector registers used    
       call      printf                           ;printf is going to output the data             
;
; END CODE EXECUTION FOR HELLOWORLD.ASM
;
;====== pop the registers back from the stack in reverse order ========================
pop r15
pop r14
pop r13
pop r12
pop r11
pop r10
pop r9
pop r8
pop rbp
pop rsi
pop rdi
pop rdx
pop rcx
pop rbx
pop rbp
;
;===== END - RETURN TO CALLED FUNCTION ===============================================
       mov       rax, 0                           ;return 0 to the called function
       ret                                        ;ret pops the stack taking away 8 bytes
; 
; http://programmingnotes.org/
;      
;===== End of DisplayHelloWorld subprogram ===========================================

Line 16 of the program defines a section that specifies memory to be stored in the data segment (whose name is .data). Only initialized data should be defined in this segment. On lines 19 to 21, several strings are declared. They will be printed with the C library, so they must be terminated with a null character (ASCII code 0). Remember there is a big difference between 0 and ’0’. Note, the number 10 is the ASCII code for a newline.

Uninitialized data should be declared in the .bss segment (named .bss on line 25). This segment gets its name from an early UNIX-based assembler operator that meant “block started by symbol.”

The code segment named .text is where instructions are placed. Note that if you are using Windows, the code label for the main routine (line 29 and 33) should have an underscore prefix, so it would be _DisplayHelloWorld. You would also need to do the same for printf (so it would be _printf). This is part of the C calling convention. This convention specifies the rules C uses when compiling code. It is very important to know this convention when interfacing C and assembly. (Note: This rule is specifically for DOS/Windows, the Linux C compiler does not prepend anything to C symbol names.)

The global directive on line 29 tells the assembler to make the asm main label global. Unlike in C, labels have internal scope by default. This means that only code in the same module can use the label. The global directive gives the specified label (or labels) external scope.

And there you have it! After you assemble the above code (see below), you should get this as your output


Welcome to My Programming Notes' Assembly Program.
Control will now be passed to the Assembly file...
--------------------------------------------

Hello World!

--------------------------------------------
Control has now been passed back from the Assembly file to the C file!
The return code is: 0
BYE!

==== ASSEMBLING THE CODE ====

This can be achieved by simply opening the teminal, and doing a copy/paste of the commands listed on the ‘driver.c’ file, lines 16 thru 19. Make sure to compile them in order for the sake of continuity.





		
		
			 (1) Compile driver.c file:                 gcc -c -Wall -m64 -std=c99 -l driver.lis -o driver.o driver.c
 (2) helloWorld.asm assembler file:         nasm -f elf64 -l helloWorld.lis -o helloWorld.o helloWorld.asm
 (3) Link all files:                        gcc -m64 -o helloWorld.out driver.o helloWorld.o
 (4) Execute in 64-bit protected mode:     ./helloWorld.out
			
				
					
				
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						 (1) Compile driver.c file:                 gcc -c -Wall -m64 -std=c99 -l driver.lis -o driver.o driver.c
 (2) helloWorld.asm assembler file:         nasm -f elf64 -l helloWorld.lis -o helloWorld.o helloWorld.asm
 (3) Link all files:                        gcc -m64 -o helloWorld.out driver.o helloWorld.o
 (4) Execute in 64-bit protected mode:     ./helloWorld.out

Be advised, that the commands to assemble the code is designed to run in 64-bit mode. If you are not running a 64-bit machine, the commands will most likely fail to assemble.

If you are running a Windows computer and would like to assemble the code, look here or here for information.

You will need to change the 64-bit registers to 32-bit registers in the “helloWorld.asm” file, aswell as removing lines 38-52 and lines 80-94 respectively in order to run the program successfully.

C++ || Char Array – Palindrome Checker Using A Character Array, ToUpper, Strlen, Strcpy, & Strcmp

February 26, 2012 admin No comments

The following is a palindrome checking program, which demonstrates more use of char array’s, ToUpper, Strlen, & Strcmp.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Character Arrays Cin.getline How to convert text in a char array from lower to uppercase How to reverse a character array Palindrome - What is it? Strlen Strcpy Strcmp While Loops For Loops Constant Variables Setw

Using a constant value, by default, this program first asks the user to enter 5 words and/or sentences that they want to compare for similarity. If the text which was entered into the program is a palindrome, the program will prompt a message to the user via cout. This program determines similarity by using the strcmp function, to compare two arrays together. This program also demonstrates how to reverse a character array, aswell as demonstrates how to convert all the text which was placed into the char array from lower to UPPERCASE.





		
		
			Palindrome Checker Using A Char Array
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Feb 26, 2012
//    Taken From: http://programmingnotes.org/
//    File:  palindrome.cpp
//    Description: Demonstrates a simple palindrome checker
// ============================================================================
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <cctype>
#include <cstring>
using namespace std;

// constant value
const int NUM_WORDS = 5;

// function prototypes
void ConvertAllToUpper(char wordsCopy[][30], char palindrome[][30]);
void ReverseCharArray(char palindrome[][30]);
void CheckIfPalindrome(char wordsCopy[][30], char palindrome[][30], char words[][30]);

int main()
{
    // declare variable
    // this is a 2-D char array, which by default, has 
    // the ability to hold 5 names, each 30 characters long
    char words[NUM_WORDS][30];
    char wordsCopy[NUM_WORDS][30];
    char palindrome[NUM_WORDS][30];

    // get data from user
    cout << "\tWelcome to the Palindrome Check System!\n";
    cout << "\nPlease enter " << NUM_WORDS << " word(s) to check for similarity:\n";
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        cout << "\t#" << index + 1 << ": ";
        cin.getline(words[index], 30);
    }

    // copy the user input into the 'wordsCopy' &
    // 'palindrome' char array
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        strcpy(wordsCopy[index], words[index]);
        strcpy(palindrome[index], words[index]);
    }

    // create a line seperator
    cout << endl;
    cout.fill('-');
    cout << left << setw(30) << "" << right << setw(30) << "" << endl;

    // re-display the input to the screen
    cout << "\nThis is what you entered into the system:\n";
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        cout << "\tText #" << index + 1 << ": " << words[index] << endl;
    }

    // create a line seperator
    cout << endl;
    cout.fill('-');
    cout << left << setw(30) << "" << right << setw(30) << "" << endl;

    // function declaration
    // convert all the text contained in the 2 arrays to
    // UPPERCASE
    ConvertAllToUpper(wordsCopy, palindrome);

    // function declaration
    // reverses all the text contained inside the char array
    // to determine if it is a palindrome
    ReverseCharArray(palindrome);

    // display the palindrome's  to the screen
    cout << "\nHere are the palindrome's:\n";

    // function declaration
    // checks to see if the text contained in the char
    // array is a palindrome or not
    CheckIfPalindrome(wordsCopy, palindrome, words);

    cin.get();
    return 0;
}// end of main

void ConvertAllToUpper(char wordsCopy[][30], char palindrome[][30])
{
    int index = 0;

    // increment thru the current char array index
    while (index < NUM_WORDS)
    {
        // increment thru each letter within the current char array index
        for (unsigned currentChar = 0; currentChar < strlen(wordsCopy[index]); ++currentChar)
        {
            // checks each letter in the current array index
            // to see if its lower or UPPERCASE
            // if its lowercase, change to UPPERCASE
            if (islower(wordsCopy[index][currentChar]))
            {
                wordsCopy[index][currentChar] = toupper(wordsCopy[index][currentChar]);
                palindrome[index][currentChar] = toupper(palindrome[index][currentChar]);
            }
        }
        ++index;
    }
}// end of ConvertAllToUpper

void ReverseCharArray(char palindrome[][30])
{
    int index = 0;

    // increment thru the current char array index
    while (index < NUM_WORDS)
    {    // get the length of the current word in the array index
        int wordLength = strlen(palindrome[index]) - 1;
        // increment thru each letter within the current char array index
        // reversing the order of the array
        for (int currentChar = 0; currentChar < wordLength; --wordLength, ++currentChar)
        {
            // copy 1st letter in the array index into temp
            char temp = palindrome[index][currentChar];
            // copy last letter in the array index into the 1st array index
            palindrome[index][currentChar] = palindrome[index][wordLength];
            // copy temp into last array index
            palindrome[index][wordLength] = temp;
        }
        ++index;
    }
}// end of ReverseCharArray

void CheckIfPalindrome(char wordsCopy[][30], char palindrome[][30], char words[][30])
{
    int palindromeCount = 0;

    // increment thru the current char array index
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        // if the contents in the 'wordsCopy' & 'palindrome'
        // are the same, then the word is a palindrome
        if (strcmp(wordsCopy[index], palindrome[index]) == 0)
        {
            cout << "\tText #" << index + 1 << ": " << words[index] << " is a palindrome" << endl;
            ++palindromeCount;
        }
    }
    if (palindromeCount == 0)
    {
        cout << "There were no palindrome's found in the current list!\n";
    }
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Feb 26, 2012
//    Taken From: http://programmingnotes.org/
//    File:  palindrome.cpp
//    Description: Demonstrates a simple palindrome checker
// ============================================================================
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <cctype>
#include <cstring>
using namespace std;
 
// constant value
const int NUM_WORDS = 5;
 
// function prototypes
void ConvertAllToUpper(char wordsCopy[][30], char palindrome[][30]);
void ReverseCharArray(char palindrome[][30]);
void CheckIfPalindrome(char wordsCopy[][30], char palindrome[][30], char words[][30]);
 
int main()
{
    // declare variable
    // this is a 2-D char array, which by default, has 
    // the ability to hold 5 names, each 30 characters long
    char words[NUM_WORDS][30];
    char wordsCopy[NUM_WORDS][30];
    char palindrome[NUM_WORDS][30];
 
    // get data from user
    cout << "\tWelcome to the Palindrome Check System!\n";
    cout << "\nPlease enter " << NUM_WORDS << " word(s) to check for similarity:\n";
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        cout << "\t#" << index + 1 << ": ";
        cin.getline(words[index], 30);
    }
 
    // copy the user input into the 'wordsCopy' &
    // 'palindrome' char array
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        strcpy(wordsCopy[index], words[index]);
        strcpy(palindrome[index], words[index]);
    }
 
    // create a line seperator
    cout << endl;
    cout.fill('-');
    cout << left << setw(30) << "" << right << setw(30) << "" << endl;
 
    // re-display the input to the screen
    cout << "\nThis is what you entered into the system:\n";
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        cout << "\tText #" << index + 1 << ": " << words[index] << endl;
    }
 
    // create a line seperator
    cout << endl;
    cout.fill('-');
    cout << left << setw(30) << "" << right << setw(30) << "" << endl;
 
    // function declaration
    // convert all the text contained in the 2 arrays to
    // UPPERCASE
    ConvertAllToUpper(wordsCopy, palindrome);
 
    // function declaration
    // reverses all the text contained inside the char array
    // to determine if it is a palindrome
    ReverseCharArray(palindrome);
 
    // display the palindrome's  to the screen
    cout << "\nHere are the palindrome's:\n";
 
    // function declaration
    // checks to see if the text contained in the char
    // array is a palindrome or not
    CheckIfPalindrome(wordsCopy, palindrome, words);
 
    cin.get();
    return 0;
}// end of main
 
void ConvertAllToUpper(char wordsCopy[][30], char palindrome[][30])
{
    int index = 0;
 
    // increment thru the current char array index
    while (index < NUM_WORDS)
    {
        // increment thru each letter within the current char array index
        for (unsigned currentChar = 0; currentChar < strlen(wordsCopy[index]); ++currentChar)
        {
            // checks each letter in the current array index
            // to see if its lower or UPPERCASE
            // if its lowercase, change to UPPERCASE
            if (islower(wordsCopy[index][currentChar]))
            {
                wordsCopy[index][currentChar] = toupper(wordsCopy[index][currentChar]);
                palindrome[index][currentChar] = toupper(palindrome[index][currentChar]);
            }
        }
        ++index;
    }
}// end of ConvertAllToUpper
 
void ReverseCharArray(char palindrome[][30])
{
    int index = 0;
 
    // increment thru the current char array index
    while (index < NUM_WORDS)
    {    // get the length of the current word in the array index
        int wordLength = strlen(palindrome[index]) - 1;
        // increment thru each letter within the current char array index
        // reversing the order of the array
        for (int currentChar = 0; currentChar < wordLength; --wordLength, ++currentChar)
        {
            // copy 1st letter in the array index into temp
            char temp = palindrome[index][currentChar];
            // copy last letter in the array index into the 1st array index
            palindrome[index][currentChar] = palindrome[index][wordLength];
            // copy temp into last array index
            palindrome[index][wordLength] = temp;
        }
        ++index;
    }
}// end of ReverseCharArray
 
void CheckIfPalindrome(char wordsCopy[][30], char palindrome[][30], char words[][30])
{
    int palindromeCount = 0;
 
    // increment thru the current char array index
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        // if the contents in the 'wordsCopy' & 'palindrome'
        // are the same, then the word is a palindrome
        if (strcmp(wordsCopy[index], palindrome[index]) == 0)
        {
            cout << "\tText #" << index + 1 << ": " << words[index] << " is a palindrome" << endl;
            ++palindromeCount;
        }
    }
    if (palindromeCount == 0)
    {
        cout << "There were no palindrome's found in the current list!\n";
    }
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

Click here to see how cin.getline works.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output
(Note: The code was compiled 2 seperate times to demonstrate different output)

====== RUN 1 ======
Welcome to the Palindrome Check System! Please enter 5 word(s) to check for similarity: #1: SteP oN nO PEts #2: My ProGramminG NoTeS #3: RaTs liVE ON No eViL StaR #4: ABLe wAs I ErE I sAw ElBa #5: LiVE Non Evil ------------------------------------------------------------ This is what you entered into the system: Text #1: SteP oN nO PEts Text #2: My ProGramminG NoTeS Text #3: RaTs liVE ON No eViL StaR Text #4: ABLe wAs I ErE I sAw ElBa Text #5: LiVE Non Evil ------------------------------------------------------------ Here are the palindrome's: Text #1: SteP oN nO PEts is a palindrome Text #3: RaTs liVE ON No eViL StaR is a palindrome Text #4: ABLe wAs I ErE I sAw ElBa is a palindrome Text #5: LiVE Non Evil is a palindrome ====== RUN 2 ====== Welcome to the Palindrome Check System! Please enter 5 word(s) to check for similarity: #1: today Is Great #2: Tomorrow is Foriegn #3: Sunday Brunch #4: Hello SkiPper #5: Mayday Ship DowN! ------------------------------------------------------------ This is what you entered into the system: Text #1: today Is Great Text #2: Tomorrow is Foriegn Text #3: Sunday Brunch Text #4: Hello SkiPper Text #5: Mayday Ship DowN!
------------------------------------------------------------ Here are the palindrome's: There were no palindrome's found in the current list!

C++ || Snippet – How To Read & Write Data From A File

February 12, 2012 admin No comments

REQUIRED KNOWLEDGE FOR THIS SNIPPET

Fstream Ifstream Ofstream Working With Files

NOTE: The data file that is used in this example can be downloaded here.

Also, in order to read in the data .txt file, you need to save the .txt file in the same directory (or folder) as your .cpp file is saved in. If you are using Visual C++, this directory will be located in

Documents > Visual Studio > Projects > [Your project name] > [Your project name]





		
		
			Input/Output Manipulation
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Feb 12, 2012
//    Taken From: http://programmingnotes.org/
//    File:  FileInput.cpp
//    Description: Demonstrates how to read data from a file
// ============================================================================
#include <iostream>
#include <fstream>
#include <cstdlib> // used for the 'exit' command
#include <cmath>
using namespace std;

int main ()
{ 
	// declare variables
	ifstream infile;
	ofstream outfile;
	double a=0,b=0,c=0;
	double root1=0, root2=0;

	// this opens the input file
	// YOUR INPUT FILE NAME GOES BELOW
	infile.open("INPUT_Quadratic_programmingnotes_freeweq_com.txt");

	// check to see if the file even exists, & if not then EXIT
	if(infile.fail()) 
	{
		cout<<"\nError, the input file could not be found!\n";
		exit(1); // exits the program
	}

	// this opens the output file
	// if the file doesnt already exist, it will be created
	outfile.open("OUTPUT_Quadratic_programmingnotes_freeweq_com.txt");

	// this loop reads in data until there is no more 
	// data contained in the file
	while(infile.good())
	{
		// this assigns the incoming data to the
		// variables 'a', 'b' and 'c'
		// NOTE: it is just like a cin >> statement
		infile >> a >> b >> c;

		// NOTE: if you want to read in data into an array
		// your declaration would be like this
		// ------------------------------------ 
		// infile >> a[counter] >> b[counter] >> c[counter];
		// ++counter;
	}

	// this does the quadratic formula calculations
	root1 = ((-b) + sqrt(pow(b,2) - (4*a*c)))/(2*a);
	root2 = ((-b) - sqrt(pow(b,2) - (4*a*c)))/(2*a);

	// this displays the numbers to screen via cout
	cout <<"For the numbers\na = "<<a<<"\nb = "<<b<<"\nc = "<<c<<endl;
	cout <<"\nroot 1 = "<<root1<<"\nroot 2 = "<<root2<<endl;
	
	// this saves the data to the output file
	// NOTE: its almost exactly the same as the cout statement
	outfile <<"For the numbers\na = "<<a<<"\nb = "<<b<<"\nc = "<<c<<endl;
	outfile <<"\nroot 1 = "<<root1<<"\nroot 2 = "<<root2<<endl;

	// close the input/output files once you are done using them
	infile.close();
	outfile.close();

	// stops the program from automatically closing
	cin.get();

	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Feb 12, 2012
//    Taken From: http://programmingnotes.org/
//    File:  FileInput.cpp
//    Description: Demonstrates how to read data from a file
// ============================================================================
#include <iostream>
#include <fstream>
#include <cstdlib> // used for the 'exit' command
#include <cmath>
using namespace std;
 
int main ()
{ 
	// declare variables
	ifstream infile;
	ofstream outfile;
	double a=0,b=0,c=0;
	double root1=0, root2=0;
 
	// this opens the input file
	// YOUR INPUT FILE NAME GOES BELOW
	infile.open("INPUT_Quadratic_programmingnotes_freeweq_com.txt");
 
	// check to see if the file even exists, & if not then EXIT
	if(infile.fail()) 
	{
		cout<<"\nError, the input file could not be found!\n";
		exit(1); // exits the program
	}
 
	// this opens the output file
	// if the file doesnt already exist, it will be created
	outfile.open("OUTPUT_Quadratic_programmingnotes_freeweq_com.txt");
 
	// this loop reads in data until there is no more 
	// data contained in the file
	while(infile.good())
	{
		// this assigns the incoming data to the
		// variables 'a', 'b' and 'c'
		// NOTE: it is just like a cin >> statement
		infile >> a >> b >> c;
 
		// NOTE: if you want to read in data into an array
		// your declaration would be like this
		// ------------------------------------ 
		// infile >> a[counter] >> b[counter] >> c[counter];
		// ++counter;
	}
 
	// this does the quadratic formula calculations
	root1 = ((-b) + sqrt(pow(b,2) - (4*a*c)))/(2*a);
	root2 = ((-b) - sqrt(pow(b,2) - (4*a*c)))/(2*a);
 
	// this displays the numbers to screen via cout
	cout <<"For the numbers\na = "<<a<<"\nb = "<<b<<"\nc = "<<c<<endl;
	cout <<"\nroot 1 = "<<root1<<"\nroot 2 = "<<root2<<endl;
	
	// this saves the data to the output file
	// NOTE: its almost exactly the same as the cout statement
	outfile <<"For the numbers\na = "<<a<<"\nb = "<<b<<"\nc = "<<c<<endl;
	outfile <<"\nroot 1 = "<<root1<<"\nroot 2 = "<<root2<<endl;
 
	// close the input/output files once you are done using them
	infile.close();
	outfile.close();
 
	// stops the program from automatically closing
	cin.get();
 
	return 0;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output

For the numbers a = 2 b = 4 c = -16
root 1 = 2 root 2 = -4

C++ || Dynamic Arrays – Create A Music Store Database Which Sorts CD Information & Display Grand Total

February 09, 2012 admin No comments

This program was presented as a homework assignment in a programming class to demonstrate the use of dynamic arrays, and pointer variables. The pointer variables which are displayed in this program are very excessive; and many are not needed, but it was good practice when trying to understand the logic behind it all.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Pointer Variables Dynamic Arrays 2-D Dynamic Arrays - How To Declare Bubble Sort While Loops For Loops Constant Variables Functions Switch Statements Toupper Strcpy Strcmp

This is an interactive program, which simulates a database for a music store, in which the user inputs data into the program (artist, CD title, genre, sales price, tax) and stores that information into multiple dynamic arrays (2-D and/or one dimensional dynamic arrays). The program will also apply any discounts that may currently be available for the selected CD genre, and applies that discount to the current CD information. When the user chooses to quit, the program will sort any data which is currently stored inside the array (by artist) in ascending order, and output the subtotal, tax applied, and grand total for all of the CD information which is entered into the array to the user.

After the program is complete, it will display a summary of the data which was stored into the array like so:

                                My Programming Notes Record Company
                                    Sales Report for 2/9/2012

Artist        Title   SalesPrice        Genre        DiscountRate     SubTotal      SalesTax   GrandTotal
Name1            CD1        12.99        Jazz         18.00%          10.65            1.26      11.91
Name2            CD2        12.99        Rap           7.00%          12.08            1.26      13.34

--------------------------------------------------------------------------------------------------------
Total (2 transactions)                                                  22.73           2.52    25.25

My Programming Notes Record Company

Sales Report for 2/9/2012

Artist Title SalesPrice Genre DiscountRate SubTotal SalesTax GrandTotal

Name1 CD1 12.99 Jazz 18.00% 10.65 1.26 11.91

Name2 CD2 12.99 Rap 7.00% 12.08 1.26 13.34

--------------------------------------------------------------------------------------------------------

Total (2 transactions) 22.73 2.52 25.25

NOTE: On some compilers, you may have to add #include < cstdlib> and #include < cstring> in order for the code to compile.





		
		
			Music Store Database
			
C++
			
			// =============================================================================
// This is an interactive program, which simulates a database for a music store 
// in which the user inputs data into the program (atrist, CD title, genre, 
// sales price, tax) and stores the data into a dynamic array. The program will 
// also apply any discounts that may currently be available to the selected CD 
// genre, and applies that   discount to the current CD. When the user choses 
// to quit, the program will  sort any data that is stored inside the array 
// (by artist) in ascending order and it will output the subtotal, tax applied, 
// and grand total for all of the CD information which is entered into the array
// =============================================================================
#include <iostream>
#include <iomanip>
#include <string>
#include <ctime>
using namespace std;

// function prototypes
double* GetDiscounts();
void DisplayMenu();
void GetCDInfo(char** &artist, char** &CDTitle, char** &genre,double* &salesPrice, double* &taxRate, int* numItems);
void GetDiscountRate(double* salesPrice,char** musicGenre, char** genre,int* numItems, double* &discountPercent,double* discountRate);
void GetSubTotal(double* salesPrice, double* discountRate, int* numItems,double* subTotal);
void GetTaxAmount(double* salesPrice, double* taxRate, int*numItems,double* salesTax);
void GetGrandTotal(double* subTotal,double* salesTax,int* numItems,double* grandTotal);
void SortData(char**artist, char**CDTitle, double*salesPrice, char**genre,double*discountPercent, double*subTotal, double*salesTax,  double*grandTotal, int* numItems);
void DisplayData(char**artist, char**CDTitle, double*salesPrice, char**genre,double*discountPercent, double*subTotal, double*salesTax, double*grandTotal, int* numItems);

// constant discount values 
// these values are defines within the
// 'GetDiscounts' function
const double* discounts = GetDiscounts();

// =============================================================================
// main
// =============================================================================
int main()
{
	//-- Declare Variables START ---//
	// numItems for artist array
	int* numItems = new int(0);

	// 2-D Dynamic array for music genres
	char** musicGenre = new char*[7];
	for(int index=0; index < 7; ++index)
	{musicGenre[index] = new char[13];}
	musicGenre[0]= "Classical";
	musicGenre[1]= "Country";
	musicGenre[2]= "International";
	musicGenre[3]= "Jazz";
	musicGenre[4]= "Pop";
	musicGenre[5]= "Rock";
	musicGenre[6]= "Rap";

	// 2-D Dynamic Array for artist name
	char** artist = new char*[50];
	for(int index=0; index < 50; ++index)
	{artist[index] = new char[20];}

	// 2-D Dynamic array for CD titles
	char** CDTitle = new char*[50];
	for(int index=0; index < 50; ++index)
	{CDTitle[index] = new char[20];}

	// 2-D Dynamic array of music genre
	char** genre = new char*[50];
	for(int index=0; index < 50; ++index)
	{genre[index] = new char[20];}

	// array for list price
	double* salesPrice = new double[20];

	// array for tax rate
	double* taxRate = new double[20];

	// array for discount amount
	double* discountRate= new double[20];

	// array for sales price
	double* subTotal = new double[20];

	// array for taxamount
	double* salesTax= new double[20];

	// array for grandTotal
	double* grandTotal = new double[20];

	// array for discount percent
	double* discountPercent = new double[20];

	// variable for the while loop menu 
	char* userInput = new char('n');

	// variable if the user wants to enter more data
	char* enterMoreData = new char('y');

	//-- Declare Variables END ---//

	// display menu
	DisplayMenu();
	cin >> userInput;

	// loop thru menu options
	while((toupper(*userInput) !='Q'))
	{
		switch(toupper(*userInput))
		{
		case 'E':
			// get artist info
			GetCDInfo(artist, CDTitle, genre, salesPrice, taxRate, numItems);
			// get discount
			GetDiscountRate(salesPrice, musicGenre, genre, numItems,discountPercent, discountRate);
			// get sub total
			GetSubTotal(salesPrice, discountRate, numItems,subTotal);
			// get tax amount
			GetTaxAmount(salesPrice, taxRate, numItems,salesTax);
			// get cash price
			GetGrandTotal(subTotal, salesTax, numItems,grandTotal);
			// ask if they want to enter more data
			cout << "nDo you want to enter more CD's? (y/n): ";
			cin >> *enterMoreData;
			if(toupper(*enterMoreData)=='Y')
			{
				(++*numItems);
			}
			else
			{
				(++*numItems);
				*userInput='q';
			}
			break;
		case 'D':
			DisplayData(artist, CDTitle, salesPrice, genre, discountPercent,subTotal,salesTax, grandTotal, numItems);
			break;
		default:
			cout<<"nYou have selected an invalid command";
			break;
		}
		//creates a line separator
		cout<<endl;
		cout<<setfill('-');
		cout<<left<<setw(30)<<""<<right<<setw(30)<<""<<endl; 

		// if user wants to enter more data, display menu to screen
		if(toupper(*enterMoreData)=='Y')
		{
			DisplayMenu();
			cin >> userInput;
		}
	}// end of while loop
	// sort the current data inside the array
	SortData(artist, CDTitle, salesPrice, genre, discountPercent,subTotal,salesTax, grandTotal, numItems);

	// display the current data inside the array
	DisplayData(artist, CDTitle, salesPrice, genre, discountPercent,subTotal,salesTax, grandTotal, numItems);

	return 0;
}// End of Main

// =============================================================================
// DisplayMenu
// displays the menu to the user
// =============================================================================
void DisplayMenu()
{
	cout<<"Welcome to the CD Management System!";
	cout<<"nFrom the following menu, select an option";
	cout<<"nnE - Enter new CD information into the database";
	cout<<"nD - Display the current information in the database";
	cout<<"nQ - Quit";
	cout<<"nn>> ";
}// End of DisplayMenu

// =============================================================================
// DisplayData
// displays the current contents in the array. If there is nothing in the array
// the program promts a message to the user
// =============================================================================
void DisplayData(char**artist, char**CDTitle, double*salesPrice, char**genre,
			  double*discountPercent, double*subTotal, double*salesTax, 
			  double*grandTotal, int* numItems)
{
	double* totSalePrice = new double(0);
	double* totSalesTax = new double(0);
	double* totgrandTotal = new double(0);

	// variables which will get the current date
    time_t t = time(0);   // get current CPU time 
    struct tm * now = localtime(& t);

	// if array is empty, display message
	if(*numItems ==0)
	{
		cout<<"nThe database is currently empty!n";
	}
	else
	{
		// displays the company header to the user
		cout<<setfill(' ');
		cout << "nttttMy Programming Notes Record Company"
			<< "ntttt    Sales Report for "<<now->tm_mon + 1<<"/"<<now->tm_mday<<"/"<<now->tm_year + 1900<<"nn";

		// displays the categories which will be shown to the user
		cout <<setw(1)<<right<<"Artist"<<setw(13)<<"Title"<<setw(13)<<"SalesPrice"
			<<setw(13)<<"Genre"<<setw(20)<<"DiscountRate"<<setw(13)<<"SubTotal"
			<<setw(13)<<"SalesTax"<<setw(13)<<"GrandTotal";
	
		// displays the data which is currently inside the array's
		cout<<fixed<<setprecision(2);
		for(int* index = new int(0); *index < *numItems; ++*index)
		{
			cout << endl;
			cout <<setw(1)<<right<<artist[*index]<<setw(15)<<CDTitle[*index]
			<<setw(13)<<salesPrice[*index]<<setw(15)<<genre[*index]<<setw(13)
				<<discountPercent[*index]*100<<"%"<<setw(15)<<subTotal[*index]<<setw(16)
				<<salesTax[*index]<<setw(13)<<grandTotal[*index];
		}

		// finds the total prices for the entire list of CD's
		for(int* index = new int(0); *index < *numItems; ++*index)
		{
			*totSalePrice+= subTotal[*index];
			*totSalesTax+= salesTax[*index];
			*totgrandTotal+= grandTotal[*index];
		}

		// creates a line separator
		cout<<setfill('-');
		cout<<endl<<endl<<left<<setw(52)<<""<<right<<setw(52)<<""<<endl;

		// displays the total to the user
		cout<< "Total ("<<*numItems<<" transactions)ttttttt"
			<<*totSalePrice<<"tt"<<*totSalesTax<<"t"<<*totgrandTotal<<endl;
	}
}// End of DisplayData

// =============================================================================
// SortData
// sorts all the data which is currently present in the arrays via bubble sort
// this function does not display any data to the user
// =============================================================================
void SortData(char**artist, char**CDTitle, double*salesPrice, char**genre,double*discountPercent, double*subTotal, double*salesTax, 
			  double*grandTotal, int* numItems)
{
	// bool which will tell us if sorting is complete
	bool sorted = false;

	// temporary variables for sorting purposes only
	char* tempArtist = new char[20];
	char* tempCDTitle= new char[20];
	char* tempGenre= new char[20];
	double* tempListPrice= new double[20];
	double* tempDiscountPercent = new double[20];
	double* tempsubTotal = new double[20];
	double* tempTaxAmt = new double[20];
	double* tempgrandTotal = new double[20];
	
	// this is the bubble sort
	// which sorts the entries by artist in ascending order
	while (sorted==false)
	{
		sorted=true;
		for(int* index= new int(0); *index < *numItems-1; ++*index)
		{
			// checks the artist to see if they are in the correct order
			if (strcmp(artist[*index],artist[*index+1]) > 0)
			{
				// swaps artist places
				strcpy(tempArtist, artist[*index]);
				strcpy(artist[*index], artist[*index+1]);
				strcpy(artist[*index+1], tempArtist);

				// swaps CD title 
				strcpy(tempCDTitle, CDTitle[*index]);
				strcpy(CDTitle[*index], CDTitle[*index+1]);
				strcpy(CDTitle[*index+1], tempCDTitle);
				
				// swaps music genre
				strcpy(tempGenre, genre[*index]);
				strcpy(genre[*index], genre[*index+1]);
				strcpy(genre[*index+1], tempGenre);
				
				// swaps the CD price
				*tempgrandTotal = grandTotal[*index];
				grandTotal[*index] = grandTotal[*index+1];
				grandTotal[*index+1] = *tempgrandTotal;
				
				// swaps the tax amount
				*tempTaxAmt = salesTax[*index];
				salesTax[*index] = salesTax[*index+1];
				salesTax[*index+1] = *tempTaxAmt;
				
				// swaps the sales price
				*tempsubTotal = subTotal[*index];
				subTotal[*index] = subTotal[*index+1];
				subTotal[*index+1] = *tempsubTotal;
				
				// swaps the discount percent
				*tempDiscountPercent = discountPercent[*index];
				discountPercent[*index] = discountPercent[*index+1];
				discountPercent[*index+1] = *tempDiscountPercent;
				
				// swaps the list price
				*tempListPrice = salesPrice[*index];
				salesPrice[*index] = salesPrice[*index+1];
				salesPrice[*index+1] = *tempListPrice;

				// sets the 'sorted' variable to false
				sorted=false;
			}// end of if statement
		}// end for loop
	}// end while loop
}// End of SortData

// =============================================================================
// GetGrandTotal
// calculates the grand total for the current transaction
// =============================================================================
void GetGrandTotal(double* subTotal,double* salesTax,int* numItems,double* grandTotal)
{
	grandTotal[*numItems]= (subTotal[*numItems])+(salesTax[*numItems]);

}// End of GetgrandTotal

// =============================================================================
// GetTaxAmount
// calculates the sales tax for the current transaction
// =============================================================================
void GetTaxAmount(double* salesPrice, double* taxRate, int*numItems,double* salesTax)
{
	salesTax[*numItems] = (salesPrice[*numItems])* (taxRate[*numItems]);
}// End of GetTaxAmount

// =============================================================================
// GetSubTotal
// gets the subtotal for the current transaction
// =============================================================================
void GetSubTotal(double* salesPrice, double* discountRate, int* numItems,double* subTotal)
{
	subTotal[*numItems] = (salesPrice[*numItems]) - (discountRate[*numItems]);
}// End of GetsubTotal

// =============================================================================
// GetDiscountRate
// gets the discount rate for the currently selected CD
// =============================================================================
void GetDiscountRate(double* salesPrice,char** musicGenre, char** genre,int* numItems, double* &discountPercent, double* discountRate)
{
	// comapres the user inputted current genre to the pre-defined
	// genres as defined in the main function, then assigns a 
	// discount to the current CD
	if(strcmp(genre[*numItems],musicGenre[0]) == 0) // if music genre is Classical
	{discountPercent[*numItems] = discounts[0];}
	else if(strcmp(genre[*numItems],musicGenre[1]) == 0) // if music genre is Country
	{discountPercent[*numItems] = discounts[1];}
	else if(strcmp(genre[*numItems],musicGenre[2]) == 0) // if music genre is International
	{discountPercent[*numItems] = discounts[2];}
	else if(strcmp(genre[*numItems],musicGenre[3]) == 0) // if music genre is Jazz
	{discountPercent[*numItems] = discounts[3];}
	else if(strcmp(genre[*numItems],musicGenre[4]) == 0) // if music genre is Pop
	{discountPercent[*numItems] = discounts[4];}
	else if(strcmp(genre[*numItems],musicGenre[5]) == 0) // if music genre is Rock
	{discountPercent[*numItems] = discounts[5];}
	else if(strcmp(genre[*numItems],musicGenre[6]) == 0) // if music genre is Rap
	{discountPercent[*numItems] = discounts[6];}
	else{discountPercent[*numItems] = discounts[4];} // if music genre is not any of these ^, then there is no discount
	
	// assign the discount rate to the current CD
	discountRate[*numItems] = (discountPercent[*numItems]) * (salesPrice[*numItems]);
}// End of GetDiscountRate

// =============================================================================
// GetCDInfo
// obtains the CD information from the user
// =============================================================================
void GetCDInfo(char** &artist, char** &CDTitle, char** &genre, 
			 double* &salesPrice, double* &taxRate, int* numItems)
{
	cin.ignore();
	cout << "nEnter the name of the artist: ";
	cin.getline(artist[*numItems],50, 'n');
	cout << "nEnter the title of the CD: ";
	cin.getline(CDTitle[*numItems],50, 'n');
	cout << "nEnter the genre: ";
	cin.getline(genre[*numItems], 20);
	cout << "nEnter the sales price $";
	cin >> salesPrice[*numItems];
	cout << "nEnter the sales tax: ";
	cin >> taxRate[*numItems];
}// End of GetInfo

// =============================================================================
// GetDiscounts
// returns the discount rate for the selected genre
// =============================================================================
double* GetDiscounts()
{
	double* temp =  new double[7];
	temp[0] = .09; // discount rate for Classical
	temp[1] = .03; // discount rate for Country
	temp[2] = .11; // discount rate for International
	temp[3] = .18; // discount rate for Jazz
	temp[4] = .00; // discount rate for Pop
	temp[5] = .10; // discount rate for Rock
	temp[6] = .07; // discount rate for Rap
	return temp;
}// http://programmingnotes.org/
			
				
					
				
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						// =============================================================================
// This is an interactive program, which simulates a database for a music store 
// in which the user inputs data into the program (atrist, CD title, genre, 
// sales price, tax) and stores the data into a dynamic array. The program will 
// also apply any discounts that may currently be available to the selected CD 
// genre, and applies that   discount to the current CD. When the user choses 
// to quit, the program will  sort any data that is stored inside the array 
// (by artist) in ascending order and it will output the subtotal, tax applied, 
// and grand total for all of the CD information which is entered into the array
// =============================================================================
#include <iostream>
#include <iomanip>
#include <string>
#include <ctime>
using namespace std;
 
// function prototypes
double* GetDiscounts();
void DisplayMenu();
void GetCDInfo(char** &artist, char** &CDTitle, char** &genre,double* &salesPrice, double* &taxRate, int* numItems);
void GetDiscountRate(double* salesPrice,char** musicGenre, char** genre,int* numItems, double* &discountPercent,double* discountRate);
void GetSubTotal(double* salesPrice, double* discountRate, int* numItems,double* subTotal);
void GetTaxAmount(double* salesPrice, double* taxRate, int*numItems,double* salesTax);
void GetGrandTotal(double* subTotal,double* salesTax,int* numItems,double* grandTotal);
void SortData(char**artist, char**CDTitle, double*salesPrice, char**genre,double*discountPercent, double*subTotal, double*salesTax,  double*grandTotal, int* numItems);
void DisplayData(char**artist, char**CDTitle, double*salesPrice, char**genre,double*discountPercent, double*subTotal, double*salesTax, double*grandTotal, int* numItems);
 
// constant discount values 
// these values are defines within the
// 'GetDiscounts' function
const double* discounts = GetDiscounts();
 
// =============================================================================
// main
// =============================================================================
int main()
{
	//-- Declare Variables START ---//
	// numItems for artist array
	int* numItems = new int(0);
 
	// 2-D Dynamic array for music genres
	char** musicGenre = new char*[7];
	for(int index=0; index < 7; ++index)
	{musicGenre[index] = new char[13];}
	musicGenre[0]= "Classical";
	musicGenre[1]= "Country";
	musicGenre[2]= "International";
	musicGenre[3]= "Jazz";
	musicGenre[4]= "Pop";
	musicGenre[5]= "Rock";
	musicGenre[6]= "Rap";
 
	// 2-D Dynamic Array for artist name
	char** artist = new char*[50];
	for(int index=0; index < 50; ++index)
	{artist[index] = new char[20];}
 
	// 2-D Dynamic array for CD titles
	char** CDTitle = new char*[50];
	for(int index=0; index < 50; ++index)
	{CDTitle[index] = new char[20];}
 
	// 2-D Dynamic array of music genre
	char** genre = new char*[50];
	for(int index=0; index < 50; ++index)
	{genre[index] = new char[20];}
 
	// array for list price
	double* salesPrice = new double[20];
 
	// array for tax rate
	double* taxRate = new double[20];
 
	// array for discount amount
	double* discountRate= new double[20];
 
	// array for sales price
	double* subTotal = new double[20];
 
	// array for taxamount
	double* salesTax= new double[20];
 
	// array for grandTotal
	double* grandTotal = new double[20];
 
	// array for discount percent
	double* discountPercent = new double[20];
 
	// variable for the while loop menu 
	char* userInput = new char('n');
 
	// variable if the user wants to enter more data
	char* enterMoreData = new char('y');
 
	//-- Declare Variables END ---//
 
	// display menu
	DisplayMenu();
	cin >> userInput;
 
	// loop thru menu options
	while((toupper(*userInput) !='Q'))
	{
		switch(toupper(*userInput))
		{
		case 'E':
			// get artist info
			GetCDInfo(artist, CDTitle, genre, salesPrice, taxRate, numItems);
			// get discount
			GetDiscountRate(salesPrice, musicGenre, genre, numItems,discountPercent, discountRate);
			// get sub total
			GetSubTotal(salesPrice, discountRate, numItems,subTotal);
			// get tax amount
			GetTaxAmount(salesPrice, taxRate, numItems,salesTax);
			// get cash price
			GetGrandTotal(subTotal, salesTax, numItems,grandTotal);
			// ask if they want to enter more data
			cout << "nDo you want to enter more CD's? (y/n): ";
			cin >> *enterMoreData;
			if(toupper(*enterMoreData)=='Y')
			{
				(++*numItems);
			}
			else
			{
				(++*numItems);
				*userInput='q';
			}
			break;
		case 'D':
			DisplayData(artist, CDTitle, salesPrice, genre, discountPercent,subTotal,salesTax, grandTotal, numItems);
			break;
		default:
			cout<<"nYou have selected an invalid command";
			break;
		}
		//creates a line separator
		cout<<endl;
		cout<<setfill('-');
		cout<<left<<setw(30)<<""<<right<<setw(30)<<""<<endl; 
 
		// if user wants to enter more data, display menu to screen
		if(toupper(*enterMoreData)=='Y')
		{
			DisplayMenu();
			cin >> userInput;
		}
	}// end of while loop
	// sort the current data inside the array
	SortData(artist, CDTitle, salesPrice, genre, discountPercent,subTotal,salesTax, grandTotal, numItems);
 
	// display the current data inside the array
	DisplayData(artist, CDTitle, salesPrice, genre, discountPercent,subTotal,salesTax, grandTotal, numItems);
 
	return 0;
}// End of Main
 
// =============================================================================
// DisplayMenu
// displays the menu to the user
// =============================================================================
void DisplayMenu()
{
	cout<<"Welcome to the CD Management System!";
	cout<<"nFrom the following menu, select an option";
	cout<<"nnE - Enter new CD information into the database";
	cout<<"nD - Display the current information in the database";
	cout<<"nQ - Quit";
	cout<<"nn>> ";
}// End of DisplayMenu
 
// =============================================================================
// DisplayData
// displays the current contents in the array. If there is nothing in the array
// the program promts a message to the user
// =============================================================================
void DisplayData(char**artist, char**CDTitle, double*salesPrice, char**genre,
			  double*discountPercent, double*subTotal, double*salesTax, 
			  double*grandTotal, int* numItems)
{
	double* totSalePrice = new double(0);
	double* totSalesTax = new double(0);
	double* totgrandTotal = new double(0);
 
	// variables which will get the current date
    time_t t = time(0);   // get current CPU time 
    struct tm * now = localtime(& t);
 
	// if array is empty, display message
	if(*numItems ==0)
	{
		cout<<"nThe database is currently empty!n";
	}
	else
	{
		// displays the company header to the user
		cout<<setfill(' ');
		cout << "nttttMy Programming Notes Record Company"
			<< "ntttt    Sales Report for "<<now->tm_mon + 1<<"/"<<now->tm_mday<<"/"<<now->tm_year + 1900<<"nn";
 
		// displays the categories which will be shown to the user
		cout <<setw(1)<<right<<"Artist"<<setw(13)<<"Title"<<setw(13)<<"SalesPrice"
			<<setw(13)<<"Genre"<<setw(20)<<"DiscountRate"<<setw(13)<<"SubTotal"
			<<setw(13)<<"SalesTax"<<setw(13)<<"GrandTotal";
	
		// displays the data which is currently inside the array's
		cout<<fixed<<setprecision(2);
		for(int* index = new int(0); *index < *numItems; ++*index)
		{
			cout << endl;
			cout <<setw(1)<<right<<artist[*index]<<setw(15)<<CDTitle[*index]
			<<setw(13)<<salesPrice[*index]<<setw(15)<<genre[*index]<<setw(13)
				<<discountPercent[*index]*100<<"%"<<setw(15)<<subTotal[*index]<<setw(16)
				<<salesTax[*index]<<setw(13)<<grandTotal[*index];
		}
 
		// finds the total prices for the entire list of CD's
		for(int* index = new int(0); *index < *numItems; ++*index)
		{
			*totSalePrice+= subTotal[*index];
			*totSalesTax+= salesTax[*index];
			*totgrandTotal+= grandTotal[*index];
		}
 
		// creates a line separator
		cout<<setfill('-');
		cout<<endl<<endl<<left<<setw(52)<<""<<right<<setw(52)<<""<<endl;
 
		// displays the total to the user
		cout<< "Total ("<<*numItems<<" transactions)ttttttt"
			<<*totSalePrice<<"tt"<<*totSalesTax<<"t"<<*totgrandTotal<<endl;
	}
}// End of DisplayData
 
// =============================================================================
// SortData
// sorts all the data which is currently present in the arrays via bubble sort
// this function does not display any data to the user
// =============================================================================
void SortData(char**artist, char**CDTitle, double*salesPrice, char**genre,double*discountPercent, double*subTotal, double*salesTax, 
			  double*grandTotal, int* numItems)
{
	// bool which will tell us if sorting is complete
	bool sorted = false;
 
	// temporary variables for sorting purposes only
	char* tempArtist = new char[20];
	char* tempCDTitle= new char[20];
	char* tempGenre= new char[20];
	double* tempListPrice= new double[20];
	double* tempDiscountPercent = new double[20];
	double* tempsubTotal = new double[20];
	double* tempTaxAmt = new double[20];
	double* tempgrandTotal = new double[20];
	
	// this is the bubble sort
	// which sorts the entries by artist in ascending order
	while (sorted==false)
	{
		sorted=true;
		for(int* index= new int(0); *index < *numItems-1; ++*index)
		{
			// checks the artist to see if they are in the correct order
			if (strcmp(artist[*index],artist[*index+1]) > 0)
			{
				// swaps artist places
				strcpy(tempArtist, artist[*index]);
				strcpy(artist[*index], artist[*index+1]);
				strcpy(artist[*index+1], tempArtist);
 
				// swaps CD title 
				strcpy(tempCDTitle, CDTitle[*index]);
				strcpy(CDTitle[*index], CDTitle[*index+1]);
				strcpy(CDTitle[*index+1], tempCDTitle);
				
				// swaps music genre
				strcpy(tempGenre, genre[*index]);
				strcpy(genre[*index], genre[*index+1]);
				strcpy(genre[*index+1], tempGenre);
				
				// swaps the CD price
				*tempgrandTotal = grandTotal[*index];
				grandTotal[*index] = grandTotal[*index+1];
				grandTotal[*index+1] = *tempgrandTotal;
				
				// swaps the tax amount
				*tempTaxAmt = salesTax[*index];
				salesTax[*index] = salesTax[*index+1];
				salesTax[*index+1] = *tempTaxAmt;
				
				// swaps the sales price
				*tempsubTotal = subTotal[*index];
				subTotal[*index] = subTotal[*index+1];
				subTotal[*index+1] = *tempsubTotal;
				
				// swaps the discount percent
				*tempDiscountPercent = discountPercent[*index];
				discountPercent[*index] = discountPercent[*index+1];
				discountPercent[*index+1] = *tempDiscountPercent;
				
				// swaps the list price
				*tempListPrice = salesPrice[*index];
				salesPrice[*index] = salesPrice[*index+1];
				salesPrice[*index+1] = *tempListPrice;
 
				// sets the 'sorted' variable to false
				sorted=false;
			}// end of if statement
		}// end for loop
	}// end while loop
}// End of SortData
 
// =============================================================================
// GetGrandTotal
// calculates the grand total for the current transaction
// =============================================================================
void GetGrandTotal(double* subTotal,double* salesTax,int* numItems,double* grandTotal)
{
	grandTotal[*numItems]= (subTotal[*numItems])+(salesTax[*numItems]);
 
}// End of GetgrandTotal
 
// =============================================================================
// GetTaxAmount
// calculates the sales tax for the current transaction
// =============================================================================
void GetTaxAmount(double* salesPrice, double* taxRate, int*numItems,double* salesTax)
{
	salesTax[*numItems] = (salesPrice[*numItems])* (taxRate[*numItems]);
}// End of GetTaxAmount
 
// =============================================================================
// GetSubTotal
// gets the subtotal for the current transaction
// =============================================================================
void GetSubTotal(double* salesPrice, double* discountRate, int* numItems,double* subTotal)
{
	subTotal[*numItems] = (salesPrice[*numItems]) - (discountRate[*numItems]);
}// End of GetsubTotal
 
// =============================================================================
// GetDiscountRate
// gets the discount rate for the currently selected CD
// =============================================================================
void GetDiscountRate(double* salesPrice,char** musicGenre, char** genre,int* numItems, double* &discountPercent, double* discountRate)
{
	// comapres the user inputted current genre to the pre-defined
	// genres as defined in the main function, then assigns a 
	// discount to the current CD
	if(strcmp(genre[*numItems],musicGenre[0]) == 0) // if music genre is Classical
	{discountPercent[*numItems] = discounts[0];}
	else if(strcmp(genre[*numItems],musicGenre[1]) == 0) // if music genre is Country
	{discountPercent[*numItems] = discounts[1];}
	else if(strcmp(genre[*numItems],musicGenre[2]) == 0) // if music genre is International
	{discountPercent[*numItems] = discounts[2];}
	else if(strcmp(genre[*numItems],musicGenre[3]) == 0) // if music genre is Jazz
	{discountPercent[*numItems] = discounts[3];}
	else if(strcmp(genre[*numItems],musicGenre[4]) == 0) // if music genre is Pop
	{discountPercent[*numItems] = discounts[4];}
	else if(strcmp(genre[*numItems],musicGenre[5]) == 0) // if music genre is Rock
	{discountPercent[*numItems] = discounts[5];}
	else if(strcmp(genre[*numItems],musicGenre[6]) == 0) // if music genre is Rap
	{discountPercent[*numItems] = discounts[6];}
	else{discountPercent[*numItems] = discounts[4];} // if music genre is not any of these ^, then there is no discount
	
	// assign the discount rate to the current CD
	discountRate[*numItems] = (discountPercent[*numItems]) * (salesPrice[*numItems]);
}// End of GetDiscountRate
 
// =============================================================================
// GetCDInfo
// obtains the CD information from the user
// =============================================================================
void GetCDInfo(char** &artist, char** &CDTitle, char** &genre, 
			 double* &salesPrice, double* &taxRate, int* numItems)
{
	cin.ignore();
	cout << "nEnter the name of the artist: ";
	cin.getline(artist[*numItems],50, 'n');
	cout << "nEnter the title of the CD: ";
	cin.getline(CDTitle[*numItems],50, 'n');
	cout << "nEnter the genre: ";
	cin.getline(genre[*numItems], 20);
	cout << "nEnter the sales price $";
	cin >> salesPrice[*numItems];
	cout << "nEnter the sales tax: ";
	cin >> taxRate[*numItems];
}// End of GetInfo
 
// =============================================================================
// GetDiscounts
// returns the discount rate for the selected genre
// =============================================================================
double* GetDiscounts()
{
	double* temp =  new double[7];
	temp[0] = .09; // discount rate for Classical
	temp[1] = .03; // discount rate for Country
	temp[2] = .11; // discount rate for International
	temp[3] = .18; // discount rate for Jazz
	temp[4] = .00; // discount rate for Pop
	temp[5] = .10; // discount rate for Rock
	temp[6] = .07; // discount rate for Rap
	return temp;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output

Welcome to the CD Management System! From the following menu, select an option
E - Enter new CD information into the database D - Display the current information in the database Q - Quit >> e Enter the name of the artist: Nm8 Enter the title of the CD: CD8 Enter the genre: Rock Enter the sales price $12.99 Enter the sales tax: .098 Do you want to enter more CD's? (y/n): y ------------------------------------------------------------ Welcome to the CD Management System! From the following menu, select an option E - Enter new CD information into the database D - Display the current information in the database Q - Quit >> e Enter the name of the artist: Nm7 Enter the title of the CD: CD7 Enter the genre: Country Enter the sales price $10.99 Enter the sales tax: .078 Do you want to enter more CD's? (y/n): y ------------------------------------------------------------ Welcome to the CD Management System! From the following menu, select an option E - Enter new CD information into the database D - Display the current information in the database Q - Quit >> e Enter the name of the artist: Nm6 Enter the title of the CD: CD6 Enter the genre: Pop Enter the sales price $11.50 Enter the sales tax: .067 Do you want to enter more CD's? (y/n): y ------------------------------------------------------------ Welcome to the CD Management System! From the following menu, select an option E - Enter new CD information into the database D - Display the current information in the database Q - Quit >> e Enter the name of the artist: Nm5 Enter the title of the CD: CD5 Enter the genre: Jazz Enter the sales price $12.24 Enter the sales tax: .045 Do you want to enter more CD's? (y/n): y ------------------------------------------------------------ Welcome to the CD Management System! From the following menu, select an option E - Enter new CD information into the database D - Display the current information in the database Q - Quit >> e Enter the name of the artist: Nm4 Enter the title of the CD: CD4 Enter the genre: Other Enter the sales price $12.99 Enter the sales tax: .094 Do you want to enter more CD's? (y/n): y ------------------------------------------------------------ Welcome to the CD Management System! From the following menu, select an option E - Enter new CD information into the database D - Display the current information in the database Q - Quit >> e Enter the name of the artist: Nm3 Enter the title of the CD: CD3 Enter the genre: Classical Enter the sales price $11.45 Enter the sales tax: .078 Do you want to enter more CD's? (y/n): y ------------------------------------------------------------ Welcome to the CD Management System! From the following menu, select an option E - Enter new CD information into the database D - Display the current information in the database Q - Quit >> e Enter the name of the artist: Nm2 Enter the title of the CD: CD2 Enter the genre: International Enter the sales price $10.99 Enter the sales tax: .093 Do you want to enter more CD's? (y/n): y ------------------------------------------------------------ Welcome to the CD Management System! From the following menu, select an option E - Enter new CD information into the database D - Display the current information in the database Q - Quit >> e
Enter the name of the artist: Nm1 Enter the title of the CD: CD1 Enter the genre: Rap Enter the sales price $12.99 Enter the sales tax: .0975 Do you want to enter more CD's? (y/n): n

                                My Programming Notes Record Company
                                    Sales Report for 2/9/2012

Artist        Title   SalesPrice        Genre        DiscountRate     SubTotal      SalesTax   GrandTotal
Nm1            CD1        12.99            Rap         7.00%          12.08            1.27        13.35
Nm2            CD2        10.99  International        11.00%           9.78            1.02        10.80
Nm3            CD3        11.45      Classical         9.00%          10.42            0.89        11.31
Nm4            CD4        12.99          Other         0.00%          12.99            1.22        14.21
Nm5            CD5        12.24           Jazz        18.00%          10.04            0.55        10.59
Nm6            CD6        11.50            Pop         0.00%          11.50            0.77        12.27
Nm7            CD7        10.99        Country         3.00%          10.66            0.86        11.52
Nm8            CD8        12.99           Rock        10.00%          11.69            1.27        12.96

--------------------------------------------------------------------------------------------------------
Total (8 transactions)                                                  89.16           7.85    97.01

My Programming Notes Record Company

Sales Report for 2/9/2012

Artist Title SalesPrice Genre DiscountRate SubTotal SalesTax GrandTotal

Nm1 CD1 12.99 Rap 7.00% 12.08 1.27 13.35

Nm2 CD2 10.99 International 11.00% 9.78 1.02 10.80

Nm3 CD3 11.45 Classical 9.00% 10.42 0.89 11.31

Nm4 CD4 12.99 Other 0.00% 12.99 1.22 14.21

Nm5 CD5 12.24 Jazz 18.00% 10.04 0.55 10.59

Nm6 CD6 11.50 Pop 0.00% 11.50 0.77 12.27

Nm7 CD7 10.99 Country 3.00% 10.66 0.86 11.52

Nm8 CD8 12.99 Rock 10.00% 11.69 1.27 12.96

--------------------------------------------------------------------------------------------------------

Total (8 transactions) 89.16 7.85 97.01

C++ || Input/Output – Using An Array, Sort Names From a Text File & Save The Sorted Names To A New Text File

February 01, 2012 admin No comments

Since we previously discussed how to sort numbers which is contained in an integer array, it is only fitting that we display a program which sorts characters that are stored in a character array.

This is an interactive program which first displays a menu to the user, allowing them to choose from 6 different modes of operation. The 6 options are described as followed:

R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit

From the available choices, the user has the option of reading in names from a file, manually entering in names themselves, displaying the current names in the array, sorting the current names in the array, clearing the current names in the array, and finally quitting the program. When the user chooses to quit the program, whatever data which is currently stored within the array will automatically be saved to the output text file.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Fstream Ifstream Ofstream Character Arrays 2D Arrays Working With Files Pass By Reference While Loops For Loops Bubble Sort Functions Switch Statements Boolean Expressions Toupper Strcpy Strcmp

The data file that is used in this example can be downloaded here.

Note: In order to read in the data .txt file, you need to save the .txt file in the same directory (or folder) as your .cpp file is saved in. If you are using Visual C++, this directory will be located in

Documents > Visual Studio 2010 > Projects > [Your project name] > [Your project name]

NOTE: On some compilers, you may have to add #include < cstdlib> and #include < cstring> in order for the code to compile.





		
		
			Sorting Names Contained In A Char Array
			
C++
			
			#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;

// const variable indicating how many names the array can hold
const int TOTALNAMES = 100;

// function prototypes
void DisplayMenu();
int ReadInData(char names[][50], ifstream &infile);
void GetUserData(char names[][50], int numberOfNames);
void ClearArray(char names[][50], int numberOfNames);
void SortArray(char names[][50], int numNames);
void DisplayArray(char names[][50], int numNames);
void SaveArrayToFile(char names[][50], int numberOfNames, ofstream &outfile);

int main()
{
	// declare variables
	ifstream infile;
	ofstream outfile;
     char names[TOTALNAMES][50];
	char userResponse = 'Q';
     int numberOfNames = 0;

	// display menu to user
	DisplayMenu();
	cin >> userResponse;

	// keep looping thru the menu until the user
	// selects Q (Quit)
	while(toupper(userResponse)!='Q')
	{
		// switch statement indicating the available choices
		// the user has to make
		switch(toupper(userResponse))
		{
		case 'R': 
			numberOfNames = ReadInData(names, infile);
			break;
		case 'E': 
			cout << "nPlease enter the number of names you want to sort: ";
			cin >> numberOfNames;
			GetUserData(names,numberOfNames);
			break;
		case 'D': 
			DisplayArray(names, numberOfNames);
			break;
		case 'C': 
			ClearArray(names,numberOfNames);
			numberOfNames=0;
			break;
		case 'S': 
			SortArray(names, numberOfNames);
			break;
		case 'Q':
			break;
		default: cout << "nThe selected option is not apart of the list!nPlease try again..";
			break;
		}
		// creates a line seperator after each task is executed
		cout<<endl;
		cout.fill('-');
          cout<<left<<setw(30)<<""<<right<<setw(30)<<""<<endl; 

		// re-display's the menu to the user
		DisplayMenu();
		cin >> userResponse;
	}

	// after the user is finished manipulating the 
	// data, save the names to the output file
	SaveArrayToFile(names, numberOfNames, outfile);

    return 0;
}// end of main

// ============================================================================

// displays options to user
void DisplayMenu()
{
	cout<<"   Welcome to the name sorting program...";
	cout<<"nFrom the following menu, select an option";
	cout<<"nR - Read in names from a file for sorting";
	cout<<"nE - Enter in names manually for sorting";
	cout<<"nD - Display the current names in the array";
	cout<<"nS - Sort the current names in the array";
	cout<<"nC - Clear the current names in the array";
	cout<<"nQ - Quitn";
     cout<<"n>> ";
}// end of DisplayMenu

// ============================================================================

// reads in data from a file
int ReadInData(char names[][50], ifstream &infile)
{
	int numberOfNames=0;
	
	// open input file
	infile.open("INPUT_UNSORTED_NAMES_programmingnotes_freeweq_com.txt");

	if(infile.fail())
	{
		cout<<"Input file could not be found!n"
			<<"Please place the input file in the correct directory..";
		return 0;
	}
	else
	{
		cout << "nReading in data from the file...";
		while(infile.good())
		{
			infile >> names[numberOfNames];
			++numberOfNames;
		}
		cout << "nSuccess!";
	}
	infile.close(); // close the infile once we are done using it
	return numberOfNames;
}// end of ReadInData

// ============================================================================

// gets data from user (names) for direct input
void GetUserData(char names[][50], int numberOfNames)
{
    cout << "nPlease enter "<<numberOfNames<<" names" << endl;

	for(int index=0; index < numberOfNames; ++index)
	{
		cout<<"nName #"<<index+1<<": ";
		cin >> names[index];
    }
}// end of GetUserData

// ============================================================================

// clears the data contained in the array
void ClearArray(char names[][50], int numNames)
{
	if(numNames==0)
	{
		cout<<"nThe array is currently empty!n";
	}
	else
	{
		cout<<"nDeleting the data contained in the array...";
		for(int index=0; index < numNames; ++index)
		{
			strcpy(names[index],"");
		}
		cout << "nClearing Complete!";
	}
}// end of ClearArray

// ============================================================================

// sorts the array via 'bubble sort'
void SortArray(char names[][50],int numNames)
{
	bool sorted = false;
	char temp[50];
	
	if(numNames==0)
	{
		cout<<"nThe array is currently empty!n";
	}
	else
	{
		cout << "nSorting the names contained in the array...";
		// this is the 'bubble sort' and will execute only
		// if there is more than 1 name contained within the array
		// If there is only one name contained in the array, 
		// there is no need to sort anything
		while((sorted == false) && (numNames > 1))
		{
			sorted = true;
			for (int index=0; index < numNames-1; ++index)
			{
				if (strcmp(names[index], names[index+1]) > 0)
				{
					strcpy(temp,names[index]);
					strcpy(names[index], names[index+1]);
					strcpy(names[index+1], temp);
					sorted = false;
				}
			}
		}
		cout << "nSuccess!";
	}
}// end of SortArray

// ============================================================================

// saves the current data which is in the arrya to the output file
void SaveArrayToFile(char names[][50], int numberOfNames, ofstream &outfile)
{
	// open output file
	outfile.open("OUTPUT_SORTED_NAMES_programmingnotes_freeweq_com.txt");

	if(outfile.fail())
	{
		cout<<"Error creating output file!";
		return;
	}
	else
	{
		if(numberOfNames==0)
		{
			cout<<"nThe array contained no names.nThere was no data to save to the output file...n";
			outfile<<"The array contained no names.nThere was no data to save to the output file...n";
		}
		else
		{
			cout<<"nSaving the current contents of the array to the ouptut file..";
			outfile<<"Sorted items which were contained within the array..n";
			for(int index=0; index < numberOfNames; ++index)
			{
				outfile <<"Name #"<<index+1<<": "
					<< names[index]<<endl;
			}
			cout << "nSuccess!n";
		}
	}
	outfile.close();
}// end of SaveArrayToFile

// ============================================================================

// displays the current contents of the array to the user
// via cout
void DisplayArray(char names[][50], int numNames)
{
	if(numNames==0)
	{
		cout<<"nThe array is currently empty!n";
	}
	else
	{
		cout << "nThe values in the array are:n";
		for (int index=0; index < numNames; ++index)
		{
			cout << names[index] << endl;
		}
		cout<<"nThere is currently "<<numNames<<" names in the array!n";
	}
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
 
// const variable indicating how many names the array can hold
const int TOTALNAMES = 100;
 
// function prototypes
void DisplayMenu();
int ReadInData(char names[][50], ifstream &infile);
void GetUserData(char names[][50], int numberOfNames);
void ClearArray(char names[][50], int numberOfNames);
void SortArray(char names[][50], int numNames);
void DisplayArray(char names[][50], int numNames);
void SaveArrayToFile(char names[][50], int numberOfNames, ofstream &outfile);
 
int main()
{
	// declare variables
	ifstream infile;
	ofstream outfile;
     char names[TOTALNAMES][50];
	char userResponse = 'Q';
     int numberOfNames = 0;
 
	// display menu to user
	DisplayMenu();
	cin >> userResponse;
 
	// keep looping thru the menu until the user
	// selects Q (Quit)
	while(toupper(userResponse)!='Q')
	{
		// switch statement indicating the available choices
		// the user has to make
		switch(toupper(userResponse))
		{
		case 'R': 
			numberOfNames = ReadInData(names, infile);
			break;
		case 'E': 
			cout << "nPlease enter the number of names you want to sort: ";
			cin >> numberOfNames;
			GetUserData(names,numberOfNames);
			break;
		case 'D': 
			DisplayArray(names, numberOfNames);
			break;
		case 'C': 
			ClearArray(names,numberOfNames);
			numberOfNames=0;
			break;
		case 'S': 
			SortArray(names, numberOfNames);
			break;
		case 'Q':
			break;
		default: cout << "nThe selected option is not apart of the list!nPlease try again..";
			break;
		}
		// creates a line seperator after each task is executed
		cout<<endl;
		cout.fill('-');
          cout<<left<<setw(30)<<""<<right<<setw(30)<<""<<endl; 
 
		// re-display's the menu to the user
		DisplayMenu();
		cin >> userResponse;
	}
 
	// after the user is finished manipulating the 
	// data, save the names to the output file
	SaveArrayToFile(names, numberOfNames, outfile);
 
    return 0;
}// end of main
 
// ============================================================================
 
// displays options to user
void DisplayMenu()
{
	cout<<"   Welcome to the name sorting program...";
	cout<<"nFrom the following menu, select an option";
	cout<<"nR - Read in names from a file for sorting";
	cout<<"nE - Enter in names manually for sorting";
	cout<<"nD - Display the current names in the array";
	cout<<"nS - Sort the current names in the array";
	cout<<"nC - Clear the current names in the array";
	cout<<"nQ - Quitn";
     cout<<"n>> ";
}// end of DisplayMenu
 
// ============================================================================
 
// reads in data from a file
int ReadInData(char names[][50], ifstream &infile)
{
	int numberOfNames=0;
	
	// open input file
	infile.open("INPUT_UNSORTED_NAMES_programmingnotes_freeweq_com.txt");
 
	if(infile.fail())
	{
		cout<<"Input file could not be found!n"
			<<"Please place the input file in the correct directory..";
		return 0;
	}
	else
	{
		cout << "nReading in data from the file...";
		while(infile.good())
		{
			infile >> names[numberOfNames];
			++numberOfNames;
		}
		cout << "nSuccess!";
	}
	infile.close(); // close the infile once we are done using it
	return numberOfNames;
}// end of ReadInData
 
// ============================================================================
 
// gets data from user (names) for direct input
void GetUserData(char names[][50], int numberOfNames)
{
    cout << "nPlease enter "<<numberOfNames<<" names" << endl;
 
	for(int index=0; index < numberOfNames; ++index)
	{
		cout<<"nName #"<<index+1<<": ";
		cin >> names[index];
    }
}// end of GetUserData
 
// ============================================================================
 
// clears the data contained in the array
void ClearArray(char names[][50], int numNames)
{
	if(numNames==0)
	{
		cout<<"nThe array is currently empty!n";
	}
	else
	{
		cout<<"nDeleting the data contained in the array...";
		for(int index=0; index < numNames; ++index)
		{
			strcpy(names[index],"");
		}
		cout << "nClearing Complete!";
	}
}// end of ClearArray
 
// ============================================================================
 
// sorts the array via 'bubble sort'
void SortArray(char names[][50],int numNames)
{
	bool sorted = false;
	char temp[50];
	
	if(numNames==0)
	{
		cout<<"nThe array is currently empty!n";
	}
	else
	{
		cout << "nSorting the names contained in the array...";
		// this is the 'bubble sort' and will execute only
		// if there is more than 1 name contained within the array
		// If there is only one name contained in the array, 
		// there is no need to sort anything
		while((sorted == false) && (numNames > 1))
		{
			sorted = true;
			for (int index=0; index < numNames-1; ++index)
			{
				if (strcmp(names[index], names[index+1]) > 0)
				{
					strcpy(temp,names[index]);
					strcpy(names[index], names[index+1]);
					strcpy(names[index+1], temp);
					sorted = false;
				}
			}
		}
		cout << "nSuccess!";
	}
}// end of SortArray
 
// ============================================================================
 
// saves the current data which is in the arrya to the output file
void SaveArrayToFile(char names[][50], int numberOfNames, ofstream &outfile)
{
	// open output file
	outfile.open("OUTPUT_SORTED_NAMES_programmingnotes_freeweq_com.txt");
 
	if(outfile.fail())
	{
		cout<<"Error creating output file!";
		return;
	}
	else
	{
		if(numberOfNames==0)
		{
			cout<<"nThe array contained no names.nThere was no data to save to the output file...n";
			outfile<<"The array contained no names.nThere was no data to save to the output file...n";
		}
		else
		{
			cout<<"nSaving the current contents of the array to the ouptut file..";
			outfile<<"Sorted items which were contained within the array..n";
			for(int index=0; index < numberOfNames; ++index)
			{
				outfile <<"Name #"<<index+1<<": "
					<< names[index]<<endl;
			}
			cout << "nSuccess!n";
		}
	}
	outfile.close();
}// end of SaveArrayToFile
 
// ============================================================================
 
// displays the current contents of the array to the user
// via cout
void DisplayArray(char names[][50], int numNames)
{
	if(numNames==0)
	{
		cout<<"nThe array is currently empty!n";
	}
	else
	{
		cout << "nThe values in the array are:n";
		for (int index=0; index < numNames; ++index)
		{
			cout << names[index] << endl;
		}
		cout<<"nThere is currently "<<numNames<<" names in the array!n";
	}
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output
(Remember to include the input file)

Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit
>> d The array is currently empty! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> q The array contained no names. There was no data to save to the output file... ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> e Please enter the number of names you want to sort: 3 Please enter 3 names Name #1: My Name #2: Programming Name #3: Notes ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> d The values in the array are: My Programming Notes There is currently 3 names in the array! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> s Sorting the names contained in the array... Success! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> d The values in the array are: My Notes Programming There is currently 3 names in the array! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> c Deleting the data contained in the array... Clearing Complete! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> r Reading in data from the file... Success! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> d The values in the array are: My Programming Notes C++ Java Assembly Lemon Dark Light Black High Low Cellphone Cat Dog Penguin Japan Peace Love Color White One Brain Eggplant Phalanx Countenance Crayons Ben Dover Eileen Bob Downe Justin Elizebeth Rick Rolled Sam Widge Liza Destruction Grove Aardvark Primal Sushi Victoria Ostrich Zebra Scrumptious Carbohydrate Sulk Ecstatic Acrobat Pneumonoultramicroscopicsilicovolcanoconiosis English Kenneth Jessica Pills Pencil Dragon Mint Chocolate Temperature Cheese Rondo Silicon Scabbiest Palpitate Invariable Henpecked Titmouse Canoodle Boobies Pressure Density Cards Twiat Tony Pink Green Yellow Duck Dodge Movie Zoo Xiomara Eggs Marshmallows Umbrella Apple Panda Brush Handle Door Knob Mask Knife Speaker Wood Orient Love There is currently 100 names in the array! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> s Sorting the names contained in the array... Success! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> d The values in the array are: Aardvark Acrobat Apple Assembly Ben Black Bob Boobies Brain Brush C++ Canoodle Carbohydrate Cards Cat Cellphone Cheese Chocolate Color Countenance Crayons Dark Density Destruction Dodge Dog Door Dover Downe Dragon Duck Ecstatic Eggplant Eggs Eileen Elizebeth English Green Grove Handle Henpecked High Invariable Japan Java Jessica Justin Kenneth Knife Knob Lemon Light Liza Love Love Low Marshmallows Mask Mint Movie My Notes One Orient Ostrich Palpitate Panda Peace Pencil Penguin Phalanx Pills Pink Pneumonoultramicroscopicsilicovolcanoconiosis Pressure Primal Programming Rick Rolled Rondo Sam Scabbiest Scrumptious Silicon Speaker Sulk Sushi Temperature Titmouse Tony Twiat Umbrella Victoria White Widge Wood Xiomara Yellow Zebra Zoo There is currently 100 names in the array! ------------------------------------------------------------ Welcome to the name sorting program... From the following menu, select an option R - Read in names from a file for sorting E - Enter in names manually for sorting D - Display the current names in the array S - Sort the current names in the array C - Clear the current names in the array Q - Quit >> q
Saving the current contents of the array to the ouptut file.. Success!

C++ || Input/Output – Find The Average of The Numbers Contained In a Text File Using an Array/Bubble Sort

January 31, 2012 admin No comments

This program highlights more practice using text files and arrays. This program is very similar to one which was previously discussed on this site, but unlike that program, this implementation omits the highest/lowest values which are found within the array via a sort.

The previously discussed program works almost as well as the current implementation, but where it fails is when the data which is being entered into the program contains multiple values of the same type. For example, using the previously discussed method to obtain the average by omitting the highest/lowest entries found within an array, if the array contained the numbers:

1, 2, 3, 3, 3, 2, 2, 1

The previous implementation would mark 1 as being the lowest number (which is correct) and it would mark 3 as being the highest number (which is also correct). The area where it fails is when it omits the highest and lowest scores found within the array. The program will skip over ALL of the numbers contained within the array which equal to 1 and 3, thus resulting in the program obtaining the wrong answer.

To illustrate, before the previous program computes its adjusted average scores, it will not only omit just 1 and 3 from the array, but it will also omit all of the 1’s and 3’s from the list, resulting in our array looking like this:

2, 2, 2

When you are finding the average of a list of numbers by omitting the highest/lowest scores, you don’t want to omit ALL of the values which may equal said numbers, but merely just the highest (last element in the array) and lowest (first element in the array) scores.

So if the previous implementation has subtle issues, why is it on this site? The previous program illustrates very well the process of finding the highest/lowest integers found within an array. It also works flawlessly for data in which there is non repeating values found within a list (i.e 1,2,3,4,5,23,6). So if you know you are reading in from a file in which there are non repeating values, the previous implementation works well. Often times though, developers do not know what type of data the incoming files will contain, so this current implementation is a better way to go, especially if it is not known exactly how many numbers are contained within a file.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Fstream Ifstream Ofstream Working With Files While Loops For Loops Bubble Sort Basic Math - Finding The Average

The data file that is used in this example can be downloaded here.

Documents > Visual Studio 2010 > Projects > [Your project name] > [Your project name]

NOTE: On some compilers, you may have to add #include < cstdlib> in order for the code to compile.





		
		
			Omit The Highest/Lowest Numbers In Array via Bubble Sort
			
C++
			
			#include <iostream>
#include <fstream>
using namespace std;

// function prototype
float FindOmittedAverage(int numbers[], int counter);

int main()
{
	// declare variables
	ifstream infile;
	ofstream outfile;
	float average=0;
	float sum =0;
	int highestNumber = -999999;
	int lowestNumber = 99999999;
	int numbers[100];

	// open the input file in which you will read data from
	infile.open("INPUT_Numbers_ programmingnotes_freeweq_com.txt");
	if(infile.fail())
	{
		cout<<"nInput file not found!n";
		exit(1); // there was an error, program exits
	}

	// open the output file in  which the compiled data will be saved to
	outfile.open("OUTPUT_Averages_ programmingnotes_freeweq_com.txt");
	if(outfile.fail())
	{
		cout <<"There was an error creating the output file, press enter to terminate program.";
		exit(1); // there was an error, program exits
	} 

	// display data to screen via cout
	cout <<"The numbers countained in the input file are: ";

	// saves data to the outfile. Notice the declaration to
	// save data to the outfile is the same as the ^ above cout
	// statment
	outfile <<"The numbers countained in the input file are: ";

	// incoming data from the file will be stored in an int array
	// so this counter will increment the array index every time the
	// program finds a new value inside the file to store inside the array
	int counter =0;

	// this while loop will read in data from the file until it reaches the end of the file
	// (i.e until there are no more number found within the file)
	// this process also stored the numbers inside the "numbers" array
	while(infile >> numbers[counter])
	{
		// 'sum' variable adds the incoming numbers together
		// computing the sum
		sum += numbers[counter];

		// finds the highest number contained within the incoming file
		if( numbers[counter] > highestNumber)
		{
			highestNumber = numbers[counter];
		}

		// finds the lowest number contained within the incoming file
		if (numbers[counter] < lowestNumber)
		{
			lowestNumber = numbers[counter];
		}

		// displays the currently found number from the file to stdout
		cout << numbers[counter] << ", ";

		// saves the currently found number from the file to the output file
		outfile << numbers[counter]<< ", ";
		++counter;
	}
	// always close your file after your done using them
	infile.close();

	// display the highest found number to stdout
	cout<< "nnThe highest and lowest numbers contained in the file are: nHighest: "
		<< highestNumber<<"nLowest: "<<lowestNumber<<endl;

	// saves the highest found number to the output file
	outfile<< "nnThe highest and lowest numbers contained in the file are: nHighest: "
		<< highestNumber<<"nLowest: "<<lowestNumber<<endl;

	// using the sum found from the above while loop, we compute the average
	average = sum/(counter);

	// display/save the average of the numbers which were contained in the 
	// file to stdout and the output file
	cout<<"nThe average of the "<<counter<<" numbers contained in the file is: "<<average<<endl;
	outfile<<"nThe average of the "<<counter<<" numbers contained in the file is: "<<average<<endl;

	// function declaration which finds the omitted average of the found numbers
	// from the file
	average = FindOmittedAverage(numbers,counter);

	// display/save the omitted average of the numbers which were contained in the 
	// file to stdout and the output file
	cout<<"nThe average of the "<<counter<<" numbers contained in the file omitting the highest and lowest scores is: "<<average<<endl;
	outfile<<"nThe average of the "<<counter<<" numbers contained in the file omitting the highest and lowest scores is: "<<average<<endl;

	// closes the outfile once we are done using it
	outfile.close();

	return 0;
}

// function takes in the 'numbers' array, and 'counter' variable from
// the main function as parameters, and computes the average, omitting 
// the highest and lowest numbers found within the array
float FindOmittedAverage(int numbers[], int counter)
{
	float sum = 0;
	float avg = 0;

	// this is a 'bubble sort' which will sort the numbers
	// contained within the array, from lowest to the highest 
	// i.e (1,2,3,4,5,6,7,8)
	for(int iteration = 1; iteration < counter; iteration++)
	{
		for(int index = 0; index < counter - iteration; index++)
		{
		// if the previous value in the array is bigger than the next, then swap them
			if(numbers[index]> numbers[index+1]) 
			{
				int temp = numbers[index];
				numbers[index] = numbers[index+1];
				numbers[index+1]= temp;
			}
		}
	}// end of sort

	// after the sorting is complete, set the highest 
	// and lowest elements in the array to zero
	numbers[0]=0;
	numbers[counter-1]=0;

	// find the sum of the newly sorted array
	// with the highest and lowest entries being deleted (set to zero)
	for(int i = 0; i < counter; i++)
	{
		sum += numbers[i];
	}

	// compute the average
	avg = sum / (counter-2);

	// return the average back to main
	return avg;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
#include <fstream>
using namespace std;
 
// function prototype
float FindOmittedAverage(int numbers[], int counter);
 
int main()
{
	// declare variables
	ifstream infile;
	ofstream outfile;
	float average=0;
	float sum =0;
	int highestNumber = -999999;
	int lowestNumber = 99999999;
	int numbers[100];
 
	// open the input file in which you will read data from
	infile.open("INPUT_Numbers_ programmingnotes_freeweq_com.txt");
	if(infile.fail())
	{
		cout<<"nInput file not found!n";
		exit(1); // there was an error, program exits
	}
 
	// open the output file in  which the compiled data will be saved to
	outfile.open("OUTPUT_Averages_ programmingnotes_freeweq_com.txt");
	if(outfile.fail())
	{
		cout <<"There was an error creating the output file, press enter to terminate program.";
		exit(1); // there was an error, program exits
	} 
 
	// display data to screen via cout
	cout <<"The numbers countained in the input file are: ";
 
	// saves data to the outfile. Notice the declaration to
	// save data to the outfile is the same as the ^ above cout
	// statment
	outfile <<"The numbers countained in the input file are: ";
 
	// incoming data from the file will be stored in an int array
	// so this counter will increment the array index every time the
	// program finds a new value inside the file to store inside the array
	int counter =0;
 
	// this while loop will read in data from the file until it reaches the end of the file
	// (i.e until there are no more number found within the file)
	// this process also stored the numbers inside the "numbers" array
	while(infile >> numbers[counter])
	{
		// 'sum' variable adds the incoming numbers together
		// computing the sum
		sum += numbers[counter];
 
		// finds the highest number contained within the incoming file
		if( numbers[counter] > highestNumber)
		{
			highestNumber = numbers[counter];
		}
 
		// finds the lowest number contained within the incoming file
		if (numbers[counter] < lowestNumber)
		{
			lowestNumber = numbers[counter];
		}
 
		// displays the currently found number from the file to stdout
		cout << numbers[counter] << ", ";
 
		// saves the currently found number from the file to the output file
		outfile << numbers[counter]<< ", ";
		++counter;
	}
	// always close your file after your done using them
	infile.close();
 
	// display the highest found number to stdout
	cout<< "nnThe highest and lowest numbers contained in the file are: nHighest: "
		<< highestNumber<<"nLowest: "<<lowestNumber<<endl;
 
	// saves the highest found number to the output file
	outfile<< "nnThe highest and lowest numbers contained in the file are: nHighest: "
		<< highestNumber<<"nLowest: "<<lowestNumber<<endl;
 
	// using the sum found from the above while loop, we compute the average
	average = sum/(counter);
 
	// display/save the average of the numbers which were contained in the 
	// file to stdout and the output file
	cout<<"nThe average of the "<<counter<<" numbers contained in the file is: "<<average<<endl;
	outfile<<"nThe average of the "<<counter<<" numbers contained in the file is: "<<average<<endl;
 
	// function declaration which finds the omitted average of the found numbers
	// from the file
	average = FindOmittedAverage(numbers,counter);
 
	// display/save the omitted average of the numbers which were contained in the 
	// file to stdout and the output file
	cout<<"nThe average of the "<<counter<<" numbers contained in the file omitting the highest and lowest scores is: "<<average<<endl;
	outfile<<"nThe average of the "<<counter<<" numbers contained in the file omitting the highest and lowest scores is: "<<average<<endl;
 
	// closes the outfile once we are done using it
	outfile.close();
 
	return 0;
}
 
// function takes in the 'numbers' array, and 'counter' variable from
// the main function as parameters, and computes the average, omitting 
// the highest and lowest numbers found within the array
float FindOmittedAverage(int numbers[], int counter)
{
	float sum = 0;
	float avg = 0;
 
	// this is a 'bubble sort' which will sort the numbers
	// contained within the array, from lowest to the highest 
	// i.e (1,2,3,4,5,6,7,8)
	for(int iteration = 1; iteration < counter; iteration++)
	{
		for(int index = 0; index < counter - iteration; index++)
		{
		// if the previous value in the array is bigger than the next, then swap them
			if(numbers[index]> numbers[index+1]) 
			{
				int temp = numbers[index];
				numbers[index] = numbers[index+1];
				numbers[index+1]= temp;
			}
		}
	}// end of sort
 
	// after the sorting is complete, set the highest 
	// and lowest elements in the array to zero
	numbers[0]=0;
	numbers[counter-1]=0;
 
	// find the sum of the newly sorted array
	// with the highest and lowest entries being deleted (set to zero)
	for(int i = 0; i < counter; i++)
	{
		sum += numbers[i];
	}
 
	// compute the average
	avg = sum / (counter-2);
 
	// return the average back to main
	return avg;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output
(Remember to include the input file)

The numbers countained in the input file are: 12, 45, 23, 46, 11, -5, 23, 33, 50, 17, 13, 25, 15, 50, The highest and lowest numbers contained in the file are: Highest: 50 Lowest: -5
The average of the 14 numbers contained in the file is: 25.5714 The average of the 14 numbers contained in the file omitting the highest and lowest scores is: 26.0833

C++ || Struct – Add One Day To Today’s Date Using A Struct

January 18, 2012 admin No comments

This program displays more practice using the structure data type, and is very similar to another program which was previously discussed here.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Functions Passing a Value By Reference Integer Arrays Structures Constant Variables Boolean Expressions

This program utilizes a struct, which is very similar to the class concept. This program first prompts the user to enter the current date in mm/dd/yyyy format. Upon obtaining the date from the user, the program then uses a struct implementation to simply add one day to the date which was entered by the user. If the day that was entered into the program by the user falls on the end of the month, the program will”roll over” the incremented date into the next month. If the user enters 12/31/2012, the program will “roll over” the incremented date into the next calendar year.

NOTE: On some compilers, you may have to add #include < cstdlib> in order for the code to compile.





		
		
			Whats Today's Date?
			
C++
			
			#include <iostream> 
using namespace std;

// struct declaration
struct Date
{
	int month;
	int day;
	int year;
};

// constants which do not change
// specifies the max values for each variable
const int MAX_DAYS = 31;
const int MAX_MONTHS = 12; 

// function prototypes
bool IsDateValid(Date dateVal);
void CalcNextDay(Date &dateVal);

int main()
{
	// initialize the structure: month, day, year
	Date dateVal = {1,18,2012};
	char backSlash = '/'; // this is a 'placeholder' variable
	
	// obtain information from user
	cout << "Please enter today's date in mm/dd/yyyy format: ";
	cin >> dateVal.month >> backSlash >> dateVal.day >> backSlash >> dateVal.year;
	
	// Checks to see if user entered valid data
	if (IsDateValid(dateVal) == false)
	{
		cout << "Invalid input...nProgram exiting...." << endl;
		exit(EXIT_FAILURE);
	} 
	
	// function declaration which calculates the next day
	CalcNextDay(dateVal);

	// display updated data to user
	cout << "The next day is " << dateVal.month << "/" << dateVal.day << "/" << dateVal.year <<endl; 
	
	return 0;
}// end of main

	// this function checks to see if the user inputted valid data
bool IsDateValid(Date dateVal)
{
     // checks to see if user inputted data falls between the specified
     // const variables as declared above
     if ((dateVal.day >= 1 && dateVal.day <= MAX_DAYS)
          &&(dateVal.month >= 1 && dateVal.month <= MAX_MONTHS))
     {
          return true;
     }
     else
     {
          return false;
     }
}// end of IsDateValid 

	// this calculates the next day & updates values via reference
void CalcNextDay(Date &dateVal)
{
	// int array which holds the max date each month has
	// from January to December
	int maxDays[12]={31,28,31,30,31,30,31,31,30,31,30,31};
	
	// bool which lets the program know if the month the
	// user entered is a max month for the specific month
	// the user inputted
	bool maxDay = false;
	
	// checks to see if user inputted day is a max date from the 
	// above array for the currently selected month which 
	// was entered by the user
	if(dateVal.day == maxDays[dateVal.month-1])
	{
		dateVal.day = 1;
		++dateVal.month;
		maxDay = true;
	}

	// checks to see if user inputted a valid date
	// for the currently selected month
	else if (dateVal.day > maxDays[dateVal.month-1])
	{
		cout << "Invalid day input - There is no such date for the selected month.nProgram exiting...." << endl;
		exit(EXIT_FAILURE);
	} 

	// if user didnt enter a max date, and the date is valid, increment the day
	else
	{
		++dateVal.day;
	}

	// if the date is 12/31/yyyy
	// increment to the next year
	if ((dateVal.month > 12)  && maxDay == true)
	{
		dateVal.month = 1;
		++dateVal.year;
	}
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream> 
using namespace std;
 
// struct declaration
struct Date
{
	int month;
	int day;
	int year;
};
 
// constants which do not change
// specifies the max values for each variable
const int MAX_DAYS = 31;
const int MAX_MONTHS = 12; 
 
// function prototypes
bool IsDateValid(Date dateVal);
void CalcNextDay(Date &dateVal);
 
int main()
{
	// initialize the structure: month, day, year
	Date dateVal = {1,18,2012};
	char backSlash = '/'; // this is a 'placeholder' variable
	
	// obtain information from user
	cout << "Please enter today's date in mm/dd/yyyy format: ";
	cin >> dateVal.month >> backSlash >> dateVal.day >> backSlash >> dateVal.year;
	
	// Checks to see if user entered valid data
	if (IsDateValid(dateVal) == false)
	{
		cout << "Invalid input...nProgram exiting...." << endl;
		exit(EXIT_FAILURE);
	} 
	
	// function declaration which calculates the next day
	CalcNextDay(dateVal);
 
	// display updated data to user
	cout << "The next day is " << dateVal.month << "/" << dateVal.day << "/" << dateVal.year <<endl; 
	
	return 0;
}// end of main
 
	// this function checks to see if the user inputted valid data
bool IsDateValid(Date dateVal)
{
     // checks to see if user inputted data falls between the specified
     // const variables as declared above
     if ((dateVal.day >= 1 && dateVal.day <= MAX_DAYS)
          &&(dateVal.month >= 1 && dateVal.month <= MAX_MONTHS))
     {
          return true;
     }
     else
     {
          return false;
     }
}// end of IsDateValid 
 
	// this calculates the next day & updates values via reference
void CalcNextDay(Date &dateVal)
{
	// int array which holds the max date each month has
	// from January to December
	int maxDays[12]={31,28,31,30,31,30,31,31,30,31,30,31};
	
	// bool which lets the program know if the month the
	// user entered is a max month for the specific month
	// the user inputted
	bool maxDay = false;
	
	// checks to see if user inputted day is a max date from the 
	// above array for the currently selected month which 
	// was entered by the user
	if(dateVal.day == maxDays[dateVal.month-1])
	{
		dateVal.day = 1;
		++dateVal.month;
		maxDay = true;
	}
 
	// checks to see if user inputted a valid date
	// for the currently selected month
	else if (dateVal.day > maxDays[dateVal.month-1])
	{
		cout << "Invalid day input - There is no such date for the selected month.nProgram exiting...." << endl;
		exit(EXIT_FAILURE);
	} 
 
	// if user didnt enter a max date, and the date is valid, increment the day
	else
	{
		++dateVal.day;
	}
 
	// if the date is 12/31/yyyy
	// increment to the next year
	if ((dateVal.month > 12)  && maxDay == true)
	{
		dateVal.month = 1;
		++dateVal.year;
	}
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output:
Note: The code was compiled 6 separate times to display the different outputs its able to produce

Please enter today's date in mm/dd/yyyy format: 1/18/2012 The next day is 1/19/2012 -------------------------------------------------------------------
Please enter today's date in mm/dd/yyyy format: 7/31/2012 The next day is 8/1/2012 ------------------------------------------------------------------- Please enter today's date in mm/dd/yyyy format: 2/28/2012 The next day is 3/1/2012 ------------------------------------------------------------------- Please enter today's date in mm/dd/yyyy format: 13/5/2012 Invalid input... Program exiting.... ------------------------------------------------------------------- Please enter today's date in mm/dd/yyyy format: 2/31/2012 Invalid day input - There is no such date for the selected month. Program exiting.... -------------------------------------------------------------------
Please enter today's date in mm/dd/yyyy format: 12/31/2012 The next day is 1/1/2013

C++ || Input/Output Text File Manipulation – Find Highest, Lowest, Average & Total Sum

January 06, 2012 admin No comments

This is a program which will utilize fstream, specifically ifstream and ofstream, to read in data from one .txt file, and it will then output selected data into an entirely new separate .txt file.

The input data file has 8 different rows, with each row containing 7 numbers on each line. The program will take in each line one at a time, manipulating the 7 numbers to receive the desired output. This program will find the highest/lowest number in each selected line, along with the total sum of all the numbers contained in that line, and the average of all the numbers. So at the end of the program, There will be 8 different sets of data compiled for each row, with the output file looking like this:

SAMPLE RUN:
- Input File - 3 5 7 3 4 5 6
- Output File - The dataset for input line #1 is: 3 5 7 3 4 5 6 The highest number is: 7 The lowest number is: 3 The total of the numbers is: 33 The average of the numbers is: 4.71

The data file that is used in this example can be downloaded here

Documents > Visual Studio > Projects > [Your project name] > [Your project name]

NOTE: On some compilers, you may have to add #include < cstdlib> in order for the code to compile.





		
		
			Text File Manipulation
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jan 6, 2012
//    Taken From: http://programmingnotes.org/
//    File:  fileInput.cpp
//    Description: Demonstrates how to read and write data to a file
// ============================================================================
#include <iostream>
#include <fstream>
using namespace std;

int main ()
{   // declare variables
    ifstream infile;
    ofstream outfile;
    int inputNumber = 0;
    int highestNum = -999999;
    int lowestNum = 999999;
    double sum = 0;
    double average = 0;
    int currentLineNum = 1;     
     
    // This opens the input file
    infile.open("INPUT_programmingnotes_freeweq_com.txt");
    if(infile.fail()) //there was an error on open, file not found
    {
        cout << "Cannot find input file, press enter to terminate program." << endl;
        exit (1); // there was an error, program exits
    }

    // This opens the output file
    outfile.open("OUTPUT_programmingnotes_freeweq_com.txt", ios::app);
    if(outfile.fail())
    {
        cout <<"There was an error opening the output file, press enter to terminate program.";
        exit(1); // there was an error, program exits
    }

    do {
        cout << "The dataset for input line #" << currentLineNum << " is: ";
        outfile << "The dataset for input line #" << currentLineNum << " is: ";

        // loops thru file until we get to the last number 
        // from the selected line 
        // (theres 7 numbers total in each line, see input file for clarification)
        for(int counter = 1; counter <= 7; counter++)
        {   
            infile >> inputNumber;

            sum += inputNumber;  // calculates the total sum of #'s for each line

            // checks to see which number is highest/lowest from 
            // each selected line
            if(inputNumber > highestNum)
            {
                highestNum = inputNumber;
            }

            if(inputNumber < lowestNum)
            {
                lowestNum = inputNumber;
            }

            // displays current number to output screen
            // and saves to file
            cout << inputNumber << "\t";
            outfile << inputNumber << "\t";
        }// end for loop

        average = sum / 7; // finds the total avg for each line

        // this displays data to the output screen
        cout << endl;
        cout << "The highest number is: " << highestNum << endl;
        cout << "The lowest number is: " << lowestNum << endl;
        cout << "The total of the numbers is: " << sum << endl;
        cout << "The average of the numbers is: " << average << endl;

        // outfile section here, saves data to file
        outfile << endl;
        outfile << "The highest number is: " << highestNum << endl;
        outfile << "The lowest number is: " << lowestNum << endl;
        outfile << "The total of the numbers is: " << sum << endl;
        outfile << "The average of the numbers is: " << average << endl << endl;
        // outfile section end

        // resets variables back to default values
        highestNum = -999999;
        lowestNum = 999999;
        sum = 0;
        average = 0;
        currentLineNum++;

        // places data on new line
        cout << endl << endl;    

    } while(!infile.eof()); // loop stops once it reaches the end of file
    
    cout << endl << endl <<"\tWe have reached the end of the file!"<< endl;
    outfile << endl << endl <<"\tWe have reached the end of the file!"<< endl << endl;
    outfile.close();  // closes outfile
    infile.close();        // closes infile

    return 0;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jan 6, 2012
//    Taken From: http://programmingnotes.org/
//    File:  fileInput.cpp
//    Description: Demonstrates how to read and write data to a file
// ============================================================================
#include <iostream>
#include <fstream>
using namespace std;
 
int main ()
{   // declare variables
    ifstream infile;
    ofstream outfile;
    int inputNumber = 0;
    int highestNum = -999999;
    int lowestNum = 999999;
    double sum = 0;
    double average = 0;
    int currentLineNum = 1;     
     
    // This opens the input file
    infile.open("INPUT_programmingnotes_freeweq_com.txt");
    if(infile.fail()) //there was an error on open, file not found
    {
        cout << "Cannot find input file, press enter to terminate program." << endl;
        exit (1); // there was an error, program exits
    }
 
    // This opens the output file
    outfile.open("OUTPUT_programmingnotes_freeweq_com.txt", ios::app);
    if(outfile.fail())
    {
        cout <<"There was an error opening the output file, press enter to terminate program.";
        exit(1); // there was an error, program exits
    }
 
    do {
        cout << "The dataset for input line #" << currentLineNum << " is: ";
        outfile << "The dataset for input line #" << currentLineNum << " is: ";
 
        // loops thru file until we get to the last number 
        // from the selected line 
        // (theres 7 numbers total in each line, see input file for clarification)
        for(int counter = 1; counter <= 7; counter++)
        {   
            infile >> inputNumber;
 
            sum += inputNumber;  // calculates the total sum of #'s for each line
 
            // checks to see which number is highest/lowest from 
            // each selected line
            if(inputNumber > highestNum)
            {
                highestNum = inputNumber;
            }
 
            if(inputNumber < lowestNum)
            {
                lowestNum = inputNumber;
            }
 
            // displays current number to output screen
            // and saves to file
            cout << inputNumber << "\t";
            outfile << inputNumber << "\t";
        }// end for loop
 
        average = sum / 7; // finds the total avg for each line
 
        // this displays data to the output screen
        cout << endl;
        cout << "The highest number is: " << highestNum << endl;
        cout << "The lowest number is: " << lowestNum << endl;
        cout << "The total of the numbers is: " << sum << endl;
        cout << "The average of the numbers is: " << average << endl;
 
        // outfile section here, saves data to file
        outfile << endl;
        outfile << "The highest number is: " << highestNum << endl;
        outfile << "The lowest number is: " << lowestNum << endl;
        outfile << "The total of the numbers is: " << sum << endl;
        outfile << "The average of the numbers is: " << average << endl << endl;
        // outfile section end
 
        // resets variables back to default values
        highestNum = -999999;
        lowestNum = 999999;
        sum = 0;
        average = 0;
        currentLineNum++;
 
        // places data on new line
        cout << endl << endl;    
 
    } while(!infile.eof()); // loop stops once it reaches the end of file
    
    cout << endl << endl <<"\tWe have reached the end of the file!"<< endl;
    outfile << endl << endl <<"\tWe have reached the end of the file!"<< endl << endl;
    outfile.close();  // closes outfile
    infile.close();        // closes infile
 
    return 0;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

LOOPS
This program utilizes one do/while loop on lines 39-97 which loops thru the input file until it reaches the end of the file. This program also uses a for loop, which is noted on line 46.

CALCULATING THE SUM
Line 50 contains the assignment operator “+=“, which will calculate a running total for all the values of each selected line.

READING IN DATA FROM FILE
This is noted in line 48, and works just like a cin statement.

OPENING FILES
File declarations, and the opening of files are highlighted on lines: 14-15, 24-25, 32-33. On line 32, the term “ios::app” means the file will append new data to the text file, instead of overwriting the old data contained within that file.

OUTPUT DATA TO FILE
This is highlighted on lines 80-84, and as you can see, the output statements are exactly the same as cout statements.

CLOSE FILES
Remember to close the files you open, as highlighted on lines 101 and 102.

Once compiling the above code, you should receive this as your output (for the 8 selected lines contained within the input text file)

The dataset for input line #1 is: 346 130 982 90 656 117 595 The highest number is: 982 The lowest number is: 90 The total of the numbers is: 2916 The average of the numbers is: 416.571
The dataset for input line #2 is: 415 948 126 4 558 571 87 The highest number is: 948 The lowest number is: 4 The total of the numbers is: 2709 The average of the numbers is: 387 The dataset for input line #3 is: 42 360 412 721 463 47 119 The highest number is: 721 The lowest number is: 42 The total of the numbers is: 2164 The average of the numbers is: 309.143 The dataset for input line #4 is: 441 190 985 214 509 2 571 The highest number is: 985 The lowest number is: 2 The total of the numbers is: 2912 The average of the numbers is: 416 The dataset for input line #5 is: 77 81 681 651 995 93 74 The highest number is: 995 The lowest number is: 74 The total of the numbers is: 2652 The average of the numbers is: 378.857 The dataset for input line #6 is: 310 9 995 561 92 14 288 The highest number is: 995 The lowest number is: 9 The total of the numbers is: 2269 The average of the numbers is: 324.143 The dataset for input line #7 is: 466 664 892 8 766 34 639 The highest number is: 892 The lowest number is: 8 The total of the numbers is: 3469 The average of the numbers is: 495.571 The dataset for input line #8 is: 151 64 98 813 67 834 369 The highest number is: 834 The lowest number is: 64 The total of the numbers is: 2396 The average of the numbers is: 342.286
We have reached the end of the file!

C++ || Hello World!

January 03, 2012 admin No comments

This page will consist of creating the typical “hello world!” application. First, you will need to create a blank project. I am using Visual C++, but any compiler will do. When you have everything loaded up, you will start your code off by entering the headers like so into your .cpp file.





		
		
			#1 - Add Header
			
C++
			
			#include <iostream>
using namespace std;
			
				
					
				
					1
2
				
						#include <iostream>
using namespace std;

The first line’s name stands for Input/Output Stream, and overall, these header files are used to handle the input/output process within your program.

Next, you are going to add the main function. This will generally look something like this

int main()
{
    // YOUR CODE GOES HERE
    return 0;
}

int main()

{

// YOUR CODE GOES HERE

return 0;

}

Adding the line of “return 0” is an exit code, and will tell the computer that your program executed without errors.

We are halfway finished, now all we have to do is say hello to the world! You will do that by adding this line of code to your program, which basically outputs data to the screen

cout << "Hello World!" << endl;

1	cout << "Hello World!" << endl;

Notice you need to add double quotes around the text you wish to output to the screen. Also, I added a line break, also knowns as “endl;” into my function. This basically is like the <_br> tag in HTML.

So when you add everything together, your full code will look something like this

#include <iostream>
using namespace std;
int main()
{
    cout << "Hello World!" << endl;
    return 0;
}// http://programmingnotes.freeweq.com

#include <iostream>

using namespace std;

int main()

{

cout << "Hello World!" << endl;

return 0;

}// http://programmingnotes.freeweq.com

And there you have it. After you compile the above code (by pressing CTRL + F5 in Visual C++), you should get this as your output

Tag Archives: Output

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Assembly || How To Obtain & Display Integer Data

Assembly || Hello World!

C++ || Char Array – Palindrome Checker Using A Character Array, ToUpper, Strlen, Strcpy, & Strcmp

C++ || Snippet – How To Read & Write Data From A File

C++ || Dynamic Arrays – Create A Music Store Database Which Sorts CD Information & Display Grand Total

C++ || Input/Output – Using An Array, Sort Names From a Text File & Save The Sorted Names To A New Text File

C++ || Input/Output – Find The Average of The Numbers Contained In a Text File Using an Array/Bubble Sort

C++ || Struct – Add One Day To Today’s Date Using A Struct

C++ || Input/Output Text File Manipulation – Find Highest, Lowest, Average & Total Sum

C++ || Hello World!

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