Implement Custom strcmp function

Code

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

int custom_strcmp(const char *a, const char *b) {
    int i=0,n=0;
    int l1=strlen(a);
    int l2=strlen(b);
    if(l1>l2){
        while(b[i]!='\0'){
            n=n+(a[i]-b[i]);
            i++;
        }
        n=n+a[i];
        return n;
    }
    else if(l2>l1){
        while(a[i]!='\0'){
            n=n+(a[i]-b[i]);
            i++;
        }
        n=n+(a[i]-b[i]);
        return n;
    }
    else{
        while(b[i]!='\0'){
            n=n+(a[i]-b[i]);
            i++;
        }
   return n;}
}

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