April 29, 2012 – My Programming Notes

Daily Archives: April 29, 2012

C++ || Snippet – How To Find The Minimum & Maximum Of 3 Numbers, Print In Ascending Order

April 29, 2012 admin No comments

This page will demonstrate how to find the minimum and maximum of 3 numbers. After the maximum and minimum numbers are obtained, the 3 numbers are displayed to the screen in ascending order.

This program uses multiple if-statements to determine equality, and uses 3 seperate int varables to store its data. This program is very basic, so it does not utilize an integer array, or any sorting methods.

NOTE: If you want to find the Minimum & Maximum of numbers contained in an integer array, click here.





		
		
			Find The Minimum & Maximum Of 3 Numbers
			
C++
			
			// ============================================================================
//    Author: K Perkins
//    Date:   Apr 29, 2012
//    Taken From: http://programmingnotes.org/
//    File:  min_mid_max.cpp
//    Description: Demonstrates how to find the minimum & maximum of 3 numbers
// ============================================================================
#include <iostream>
using namespace std;

int main()
{
    // declare variables
    int a=0;
    int b=0;
    int c=0;
    int max=0;
    int min=0;
    int middle=0;
    
    // get data from user
    cout<<"Please enter 3 numbers: ";
    cin >> a >> b >> c;
    
    // display information back to the user
    cout <<"The numbers you just entered are: "<<a<<" "<<b<<" "<<c<<endl;
    
    // check for the highest number
    if(a > b && a > c)
    {
        max = a;
    }
    else if(b > a && b > c)
    {
        max = b;
    }
    else
    {
        max = c;
    }
    
    // check for the lowest number
    if(a < b && a < c)
    {
        min = a;
    }
    else if(b < a && b < c)
    {
        min = b;
    }
    else
    {
        min = c;
    }
    
    // use the 'min' and 'max' variables from above ^ to find
    // the 'middle' value
    if((max == a && min == b) || (max == b && min == a))
    {
        middle = c;
    }
    else if((max == b && min == c) || (max == c && min == b))
    {
        middle = a;
    }
    else
    {
        middle = b;
    }
    
    // display data to the screen
    cout<<"nThe maximum number is: "<<max;
    cout<<"nThe minimum number is: "<<min;
    cout<<"nThe numbers in order are: "<<min<<" "<<middle<< " "<<max<<endl;
    
    return 0;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: K Perkins
//    Date:   Apr 29, 2012
//    Taken From: http://programmingnotes.org/
//    File:  min_mid_max.cpp
//    Description: Demonstrates how to find the minimum & maximum of 3 numbers
// ============================================================================
#include <iostream>
using namespace std;
 
int main()
{
    // declare variables
    int a=0;
    int b=0;
    int c=0;
    int max=0;
    int min=0;
    int middle=0;
    
    // get data from user
    cout<<"Please enter 3 numbers: ";
    cin >> a >> b >> c;
    
    // display information back to the user
    cout <<"The numbers you just entered are: "<<a<<" "<<b<<" "<<c<<endl;
    
    // check for the highest number
    if(a > b && a > c)
    {
        max = a;
    }
    else if(b > a && b > c)
    {
        max = b;
    }
    else
    {
        max = c;
    }
    
    // check for the lowest number
    if(a < b && a < c)
    {
        min = a;
    }
    else if(b < a && b < c)
    {
        min = b;
    }
    else
    {
        min = c;
    }
    
    // use the 'min' and 'max' variables from above ^ to find
    // the 'middle' value
    if((max == a && min == b) || (max == b && min == a))
    {
        middle = c;
    }
    else if((max == b && min == c) || (max == c && min == b))
    {
        middle = a;
    }
    else
    {
        middle = b;
    }
    
    // display data to the screen
    cout<<"nThe maximum number is: "<<max;
    cout<<"nThe minimum number is: "<<min;
    cout<<"nThe numbers in order are: "<<min<<" "<<middle<< " "<<max<<endl;
    
    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

Please enter 3 numbers: 89 56 1987 The numbers you just entered are: 89 56 1987
The maximum number is: 1987 The minimum number is: 56 The numbers in order are: 56 89 1987

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

April 29, 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 is very similar to an earlier snippet which was presented on this site, but in this example, the user has the option of choosing which file they want to manipulate. This program also demonstrates how to read in data from a file (numbers), manipulate that data, and output new data into a different text file.

REQUIRED KNOWLEDGE FOR THIS SNIPPET

Fstream Ifstream Ofstream Working With Files C_str() - Convert A String To Char Array Equivalent Getline - String Version

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 2010 > Projects > [Your project name] > [Your project name]





		
		
			User Specified Input/Output Manipulation
			
C++
			
			#include <iostream>
#include <fstream>
#include <string>
#include <cmath>
#include <cstdlib>
using namespace std;

int main() 
{
    // declare variables
    // char fileName[80];
    string fileName;    
    ifstream infile;
    ofstream outfile;
    double a=0,b=0,c=0;
    double root1=0, root2=0;    
    
    // get the name of the file from the user
    cout << "Please enter the name of the file: ";    
    getline(cin, fileName);
    
    // ^ you could also use a character array instead
    // of a string. Your getline declaration would look
    // like this:
    // ---------------------------------------------
    // cin.getline(fileName,80);


    // this opens the input file
    // NOTE: you need to convert the string to a 
    // char array using the function "c_str()"
    infile.open(fileName.c_str());
    
    // ^  if you used a char array as the file name instead 
    // of a string, the declaration to open the file 
    // would look like this:
    // ---------------------------------------------
    // infile.open(fileName);
    
    // 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);
    }
    
    // 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.peek() != EOF)
    {
        // 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 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 numbersna = "<<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 numbersna = "<<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
    cout<<"nPress ENTER to continue...";
    cin.get();

    return 0;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
#include <fstream>
#include <string>
#include <cmath>
#include <cstdlib>
using namespace std;
 
int main() 
{
    // declare variables
    // char fileName[80];
    string fileName;    
    ifstream infile;
    ofstream outfile;
    double a=0,b=0,c=0;
    double root1=0, root2=0;    
    
    // get the name of the file from the user
    cout << "Please enter the name of the file: ";    
    getline(cin, fileName);
    
    // ^ you could also use a character array instead
    // of a string. Your getline declaration would look
    // like this:
    // ---------------------------------------------
    // cin.getline(fileName,80);
 
 
    // this opens the input file
    // NOTE: you need to convert the string to a 
    // char array using the function "c_str()"
    infile.open(fileName.c_str());
    
    // ^  if you used a char array as the file name instead 
    // of a string, the declaration to open the file 
    // would look like this:
    // ---------------------------------------------
    // infile.open(fileName);
    
    // 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);
    }
    
    // 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.peek() != EOF)
    {
        // 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 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 numbersna = "<<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 numbersna = "<<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
    cout<<"nPress ENTER to continue...";
    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

Please enter the name of the file: INPUT_Quadratic_programmingnotes_freeweq_com.txt
For the numbers a = 2 b = 4 c = -16 root 1 = 2 root 2 = -4
Press ENTER to continue...

Daily Archives: April 29, 2012

C++ || Snippet – How To Find The Minimum & Maximum Of 3 Numbers, Print In Ascending Order

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

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