Pset1: Error when trying to assign single digits of int variable to array using for loop

Question

I'm currently working on Credit. I'm trying to find the first two digits of the card number using a for loop. I've created an array named firstdigits with two elements. Then I've created a for loop to assign the first two digits of the card number to the first and second elements of the array, respectively. However I keep getting an error message indicating the lines firstdigits[0] = card[z]; and firstdigits[1] = card[z]; which says 'subscripted value is not an array, pointer, or vector.' Could someone help, please?

#include <cs50.h>
#include <stdio.h>
#include <string.h>
int main(void)
{
long long card = get_long_long();


int firstdigits[1];

for (int z = 0; z < 2; z++)
{
     if (z == 0)
    {
        firstdigits[0] = card[z];
    }

    if (z == 1)
    {
        firstdigits[1] = card[z];
    }
}

Answer 1

A simple way is a loop over a copy of the number. number % 10 returns the last digit, while number / 10 returns the number with last digit removed. Remove digits from the copy until it's less than 100 and you have your first two digits.

int firstdigits[1]; makes place for one integer at index 0. It doesn't have a firstdigits[1], that would require it to be at least of length 2.