Write a C Program to Check whether String is Palindrome or not using Recursion

Recursion : :

• Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.

• The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.

• Recursive functions are very useful to solve many mathematical problems, such as calculating the factorial of a number, generating Fibonacci series, etc.

Problem : :

The following C program, with recursion, determines whether the entered string is a palindrome or not. A palindrome is a word, phrase or sentence that reads the same backward or forward.

Below is the source code for C Program to Check whether String is Palindrome or not using Recursion which is successfully compiled and run on Windows System to produce desired output as shown below :

SOURCE CODE : :

/* C Program to Check whether String is Palindrome or not using Recursion */


#include <stdio.h>
#include <string.h>
 
void check(char [], int);
 
int main()
{
    char word[15];
 
    printf("Enter a word to check if it is a palindrome\n");
    scanf("%s", word);
    check(word, 0);
 
    return 0;
}
 
void check(char word[], int index)
{
    int len = strlen(word) - (index + 1);
    if (word[index] == word[len])
    {
        if (index + 1 == len || index == len)
        {
            printf("The entered word is a palindrome\n");
            return;
        }
        check(word, index + 1);
    }
    else
    {
        printf("The entered word is not a palindrome\n");
    }
}

Output :

***************** OUTPUT ********************


***************** FIRST RUN *****************

Enter a word to check if it is a palindrome 
CodezClub

The entered word is not a palindrome

***************** SECOND RUN *****************

Enter a word to check if it is a palindrome
radar

The entered word is a palindrome