How to reverse a string (C++)

How to reverse a string

Reverse() takes the string as an input parameter and returns the reversed string.

Example

For example. if the input to this function is Saad Bin Saulat, then it will return  taluaS niB daaS.

Summary of Reverse()

Reverse() starts from the first index of the string and goes to the half length of the string. At each iteration it swap 2 elements of the string, i.e

In first iteration, it swaps first and the last element,

In the second iteration, it swaps second and the second last element,

And so on…

Reverse() uses Swap() function to swap 2 elements of the string.

Summary of Swap()

Swap() takes 2 input parameters which are the pointers to the 2 elements to be swapped.

First a temporary pointer temp is declared,

char * temp;

which holds the data during swapping,

then the second element var2 is stored in temp

temp = var2;

then the first element var1 is placed in var2

var2 = var1;

and at the last the value of temp is assigned to var1

var1 = temp;

Code

#include "stdafx.h"

#include "iostream"

#include "conio.h"

using namespace std;

void Swap ( char * var1 , char * var2 )

{

       char * temp;

       temp = var2;

       var2 = var1;

       var1 = temp;

}

char * Reverse( char str[] )

{

       int length = strlen( str );

       int j = length - 1;

       int temp;

       for ( int i = 0; i < length / 2; i++ , j-- )

       {

              Swap( str[i] , str[j] );

       }

return str;

}

int main()

{

       char str[]="Saad Bin Saulat";

       cout << Reverse( str ) << endl;

       cout << Reverse( str ) << endl;

       _getche();

       return 0;

}

Output

taluaS niB daaS

Saad Bin Saulat