C Program to Check if a Given String is Palindrome


Given a string, write a c function to check if it is palindrome or not.
A string is said to be palindrome if reverse of the string is same as string. For example, “abba” is palindrome, but “abbc” is not palindrome.


1) Find length of str. Let length be n.
2) Initialize low and high indexes as 0 and n-1 respectively.
3) Do following while low index ‘l’ is smaller than high index ‘h’.
…..a) If str[l] is not same as str[h], then return false.
…..b) Increment l and decrement h, i.e., do l++ and h–.
4) If we reach here, it means we didn’t find a mis

Following is C implementation to check if a given string is palindrome or not.

#include <stdio.h>
#include <string.h>

// A function to check if a string str is palindrome
void isPalindrome(char str[])
    // Start from leftmost and rightmost corners of str
    int l = 0;
    int h = strlen(str) - 1;

    // Keep comparing characters while they are same
    while (h > l)
        if (str[l++] != str[h--])
            printf("%s is Not Palindrome", str);
    printf("%s is palindrome", str);

// Driver program to test above function
int main()
    return 0;


abba is palindrome
abbccbba is palindrome
geeks is Not Palindrome

Recursive function to check if a string is palindrome

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