#include <stdio.h>
#include <stdlib.h>
#include "sin_helpers.c"

int populate_array(int, int *);
int check_sin(int *);


int main(int argc, char **argv) {
    // TODO: Verify that command line arguments are valid.
    if (!(argc == 2)) {
        return 2;
    }
    // TODO: Parse arguments and then call the two helpers in sin_helpers.c
    // to verify the SIN given as a command line argument.
    int socialInsuranceNum =  strtol(argv[1], NULL, 10);
    int numArray[9];
    int ans;
    populate_array(socialInsuranceNum, numArray);
    ans = check_sin(numArray);
    printf("%d", ans);
    return ans;
}

My code is supposed to print if the SIN is valid but it states there are multiple definitions for check_sin