Implement Custom strcmp function

Code

#include <stdio.h>

int custom_strcmp(const char *a, const char *b) {
    // Your logic here
    int r = 0;
    while (*a != '\0' && *b != '\0') {
        if (*a != *b) {
            r =(unsigned char)*a;
            r -= (unsigned char)*b;
            return r;
        }
        a++;
        b++;
    }

    if (*a) {
         r =(unsigned char)*a;
    }
    else if (*b) {
        r = -1 * (unsigned char)*b;
    }
    return r;
}

int main() {
    char a[101], b[101];
    fgets(a, sizeof(a), stdin);
    fgets(b, sizeof(b), stdin);

    // Remove newline
    int i = 0;
    while (a[i]) {
        if (a[i] == '\n') { a[i] = '\0'; break; }
        i++;
    }
    i = 0;
    while (b[i]) {
        if (b[i] == '\n') { b[i] = '\0'; break; }
        i++;
    }

    printf("%d", custom_strcmp(a, b));
    return 0;
}

Solving Approach