ZfCEw8 - Online C Compiler & Debugging Tool

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

char* setPalindrome(char *s) {
    int n = strlen(s);
    int len = n * 2;
    char *ret = (char *)malloc(sizeof(char) * (len + 1));
    strcpy(ret, s);
    for (int i = 0; i < n; i++) {
        ret[n + i] = s[n - 1 - i];
    }
    ret[len] = '\0';
    return ret;
}

int main(void) {
    char s[101];
    scanf("%100s", s);
    char *pal = setPalindrome(s);
    printf("%s\n", pal);
    free(pal);
    return 0;
}