A palindrome is a sequence that, when reversed, looks exactly like the original. For example, abba, level, 232, and so on.

Let’s look at a program that uses the recursive technique to determine whether a number is a palindrome or not.

#include<stdio.h>

// declaring the recursive function
int isPalin(int );

int n;

int main()
{

    int palindrome;
    printf("\n\nEnter a number to check for Palindrome: ");
    scanf("%d", &n);
    palindrome = isPalin(n);
    if(palindrome == 1)
        printf("\n\n\n%d is palindrome\n\n", n);
    else
        printf("\n\n\n%d is not palindrome\n\n", n);

    return 0;
}

int isPalin(int num)
{
    static int sum = 0;
    if(num != 0)
    {
        sum = sum *10 + num%10;
        isPalin(num/10);   // recursive call same as while(n!=0) using loop
    }
    else if(sum == n)
        return 1;
    else
        return 0;
}

Output:

When the input is 121.

Enter a number to check for Palindrome: 121
121 is palindrome

When the input is 243.

Enter a number to check for Palindrome: 243
243 is not palindrome

Note: also read about the Command Line Argument

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Rabecca Fatima

Staying up to the mark is what defines me. Hi all! I’m Rabecca Fatima a keen learner, great enthusiast, ready to take new challenges as stepping stones towards flying colors.