CS50x Coding Contest 2016 Practice - Substring Challenge

substring.c

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

#include "cs50.h"

int main(void)
{
    char* input = GetString();
    char* substring = GetString();
    
    int location = 0;
    int i = 0;
    int j = 0;
    
    while (input[i] != '\0')
    {
        // either the characters match here or if the wildcard is used incrememnt both strings and compare again
        while (input[i] == substring[j] || substring[j] == '*')
        {
            i++;
            j++;
        }
        if (substring[j] == '\0')
        {
            printf("%i", location);
            return 0;
        }
    
        location++;
        i++;
        j = 0; // need to reset the substring back to the first character if we reach this far
    }
    
    printf("-1");
    return 1;
}