Question

How to check whether a string is palindrome or not using recursion in C

Answer 1

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

void check_palindrome_recursion(char s[], int index) {
    int fromend = strlen(s) - (index + 1);
    
    if (s[index] == s[fromend]) {
        if (index + 1 == fromend || index == fromend) {
            printf("Palindrome\n");
            return;
        }
        check_palindrome_recursion(s, index + 1);
    }
    else {
        printf("Not palindrome\n");
    }
}

int main() {
    char s[10] = "abcdcba";

    check_palindrome_recursion(s, 0);
    
    return 0;
}




/*
run:

Palindrome

*/

 

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Answer 2

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

int palindrome_recursion(char s[], int index) {
    int fromend = strlen(s) - (index + 1);
    
    if (s[index] == s[fromend]) {
        if (index + 1 == fromend || index == fromend) {
            return 1;
        }
        palindrome_recursion(s, index + 1);
    }
    else {
        return 0;
    }
}

int main() {
    char s[10] = "abcdcba";

    if (palindrome_recursion(s, 0)) {
        printf("Palindrome\n");
    }
    else {
        printf("Not palindrome\n");
    }
    
    
    return 0;
}




/*
run:

Palindrome

*/

 

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