C Program To Reverse A Given String

Advertisements
Advertisements

The program to reverse a given string takes the input string and output reverse of the string. Each of the characters from the input string is extracted one at a time to achieve this task.

The program is compiled using Dev-C++ compiler version 4.9.9.2 installed on a Windows 7 64-bit system. However, you can use any other standard C compiler to run this program. To get an error-free program change the source code according to your compiler specifications.

You must be familiar with following C programming concepts to understand this program.

Problem Definition

The program takes an input string at run-time using the builtin function gets (str) where str is a character array. In this array of characters, the beginning characters are exchanged with the ending characters of the string with the help of a temp variable.

For example

Advertisements

If the string is “ELEPHANT”. The letter is ‘E’ and ‘T’ are exchanged until all characters are reversed. The final output is TNAHPELE.

Program Code Reverse a String

#include <string.h>
#include <stdio.h>
#include <conio.h>
int main()
{
    char str[100],temp;
    int i,j=0;
    printf("\n Enter the String: ");
    gets(str);
    i=0;
    j = strlen(str)-1;
    while(i<j)
          {
        temp = str[i];
        str[i] = str[j];
        str[j] = temp;
        i++;
        j--;
    }
    printf("\n Reverse String is %s",str);
    getch();
}

Output

The output of the above program is given below. When the program ask for a string input, the user enters – MATHEMATICS. The program reverses the string and give following output.

Enter the String: MATHEMATICS
Reverse String is SCITAMEHTAM
Advertisements
Advertisements
Advertisements