Daily Archives: March 1, 2012
C++ || 8 Different Ways To Reverse A String/Character Array In C++
This page will consist of 8 different ways to reverse a character array, and a string literal (std::string).
REQUIRED KNOWLEDGE FOR THE PROGRAMS
Character Arrays
String Literals
Cin.getline - Use For Char Arrays
Getline - Use For std::string
Length
Strlen
Strcpy
While Loops
For Loops
Recursion - What is it?
#include < algorithm>
#include < stack>
The methods on this page will be broken up into sections. This page will list:
(3) methods which reverses string literals (std::string)
(4) methods which reverses character arrays
(1) method which utilizes the stack to "reverse" a character sequence
Some methods listed on this page demonstrates the use of reversing a character sequence without the use of strlen/length.
======= REVERSE AN STD::STRING =======
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#include <iostream> #include <algorithm> #include <string> using namespace std; int main() { // declare variable string name=""; cout << "Enter your name: "; getline(cin,name); // built in C++ function to reverse an std::string reverse(name.begin(), name.end()); cout <<"\nYour name reversed is: " <<name << endl; return 0; }// http://programmingnotes.org/ |
SAMPLE OUTPUT
Enter your name: My Programming NotesYour name reversed is: setoN gnimmargorP yM
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#include <iostream> #include <string> using namespace std; // function prototypes void Reverse(string name); int main() { // declare variable string name=""; // get user data cout<<"Enter your name: "; getline(cin,name); cout<<"\nYour name reversed is: "; // function declaration Reverse(name); cout<<endl; return 0; }// end of main void Reverse(string name) { if(name == "") // the base case { return; } else // the recursive step { Reverse(name.substr(1)); cout<<name.at(0); } }// http://programmingnotes.org/ |
SAMPLE OUTPUT
Enter your name: My Programming NotesYour name reversed is: setoN gnimmargorP yM
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#include <iostream> #include <string> using namespace std; // function prototypes void Reverse(string name); int main() { // declare variable string name=""; // get user data cout<<"Enter your name: "; getline(cin,name); cout<<"\nYour name reversed is: "; // function declaration Reverse(name); cout<<endl; return 0; }// end of main void Reverse(string name) { // get the length of the string int nameLength = name.length()-1; while(nameLength >= 0) { cout<<name[nameLength]; --nameLength; } }// http://programmingnotes.org/ |
SAMPLE OUTPUT
Enter your name: My Programming NotesYour name reversed is: setoN gnimmargorP yM
======= REVERSE A CHARACTER ARRAY =======
The following will demonstrate (4) methods which reverses a character array.
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#include <iostream> using namespace std; // function prototype void Reverse(char name[]); int main() { // declare variable char name[30]; // get user data cout<<"Enter your name: "; cin.getline(name, sizeof(name)); cout<<"\nYour name reversed is: "; // function declaration Reverse(name); cout<<endl; return 0; }// end of main void Reverse(char name[]) { if(*name=='\0') // the base case { return; } else // the recursive step { Reverse(name+1); cout<<*(name); } }// http://programmingnotes.org/ |
SAMPLE OUTPUT
Enter your name: My Programming NotesYour name reversed is: setoN gnimmargorP yM
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#include <iostream> using namespace std; // function prototypes void Reverse(char name[]); int main() { // declare variable char name[30]; // get user data cout<<"Enter your name: "; cin.getline(name, sizeof(name)); cout<<"\nYour name reversed is: "; // function declaration Reverse(name); cout<<endl; return 0; }// end of main void Reverse(char name[]) { int nameLength = 0; //get the length of array while(name[nameLength] != '\0') { ++nameLength; } //decrease the length of by 1 --nameLength; // display reversed string while(nameLength >= 0) { cout<<name[nameLength]; --nameLength; } }// http://programmingnotes.org/ |
SAMPLE OUTPUT
Enter your name: My Programming NotesYour name reversed is: setoN gnimmargorP yM
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#include <iostream> #include <cstring> using namespace std; // function prototypes void Reverse(char name[]); int main() { // declare variable char name[30]; // get user data cout<<"Enter your name: "; cin.getline(name, sizeof(name)); // function declaration Reverse(name); cout<<"\nYour name reversed is: "<< name<<endl; return 0; }// end of main void Reverse(char name[]) { // private variables int nameLength = 0; char copy[30]; strcpy(copy,name); //get lenght of array while(name[nameLength] != '\0') { ++nameLength; } //decrease the length of by 1 --nameLength; // reverse the array for(int x = 0; x <= nameLength; ++x) { // rearange the order of the two arrays name[nameLength - x] = copy[x]; } }// http://programmingnotes.org/ |
SAMPLE OUTPUT
Enter your name: My Programming NotesYour name reversed is: setoN gnimmargorP yM
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#include <iostream> #include <cstring> using namespace std; // function prototypes void Reverse(char name[]); int main() { // declare variable char name[30]; // get user data cout<<"Enter your name: "; cin.getline(name, sizeof(name)); // function declaration Reverse(name); cout<<"\nYour name reversed is: "<< name<<endl; return 0; }// end of main void Reverse(char name[]) { // get the length of the current word in the array index int nameLength = strlen(name)-1; // increment thru each letter within the current char array index // reversing the order of the array for(int currentChar=0; currentChar < nameLength; --nameLength, ++currentChar) { // copy 1st letter in the array index into temp char temp = name[currentChar]; // copy last letter in the array index into the 1st array index name[currentChar] = name[nameLength]; // copy temp into last array index name[nameLength] = temp; } }// http://programmingnotes.org/ |
SAMPLE OUTPUT
Enter your name: My Programming NotesYour name reversed is: setoN gnimmargorP yM
======= REVERSE A CHARACTER SEQUENCE USING A STACK =======
The following will demonstrate (1) method which reverses a character sequence using the STL stack.
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#include <iostream> #include <stack> using namespace std; // function prototypes void Reverse(stack<char> &name); int main() { // using the internal system stack stack<char> name; char singleChar; cout<<"Enter your name: "; while(cin.get(singleChar) && singleChar != '\n') { name.push(singleChar); } cout<<"\nYour name reversed is: "; // function declaration Reverse(name); cout<<endl; return 0; }// end of main void Reverse(stack<char> &name) { while(!name.empty()) { cout << name.top(); name.pop(); } }// http://programmingnotes.org/ |
SAMPLE OUTPUT
Enter your name: My Programming NotesYour name reversed is: setoN gnimmargorP yM