Qn-4.c

Problem Statement

Qn-4.c

Write a program to check a string is palindrome or not using user-defined function.

Source Code

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

bool isPalindrome(char str[]);

int main() {
    char str[100];

    printf("Enter a string: ");
    fgets(str, sizeof(str), stdin);
    str[strcspn(str, "\n")] = '\0';
    if (isPalindrome(str)) {
        printf("\"%s\" is a palindrome.\n", str);
    } else {
        printf("\"%s\" is not a palindrome.\n", str);
    }
    return 0;
}

bool isPalindrome(char str[]) {
    int left = 0;
    int right = strlen(str) - 1;

    while (right > left) {
        if (tolower(str[left]) != tolower(str[right])) {
            return false; 
        }
        left++;
        right--;
    }
    return true; 
}

---

● Author - Amit Dutta · Updated - 06 Mar 2026