Question

In C language:

A palindrome is a string that reads the same forwards or backwards; for example dad, mom, deed (i.e., reversing a palindrome produces the same string ). Write a recursive, bool-valued function, isPalindrome that accepts a string and returns whether the string is a palindrome.

Answer 1

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

int isPalindrome(char *str) {
    int i, len = strlen(str);
    for(i = 0; i < len; ++i) {    // go through all indexes of the array
        if(str[i] != str[len-i-1]) {    // if it's not a palindrome
            return 0;   // return false
        }
    }
    return 1;   // if it's a palindrome return true.
}

int main() {
    printf("%d\n", isPalindrome("dad"));  // prints 1 for true
    printf("%d\n", isPalindrome("mom"));  // prints 1 for true
    printf("%d\n", isPalindrome("madam"));  // prints 1 for true
    printf("%d\n", isPalindrome("hello"));  // prints 0 for false
    return 0;
}