#include <cs50.h>
#include <stdio.h>

int main(int argc, string argv[])
{
    int n;

    // collect user input
    do
    {
        printf("Please enter a positive decimal value: ");
        n = GetInt();
    }
    while (n <= 0);

    // create array to store binary digits
    int binary[31];

    // keep track of position in binary array
    int digit;

    // calculate binary digits by repeatedly dividing by 2
    for (digit = 0; n != 0; digit++, n /= 2)
        // store binary digits in array
        binary[digit] = n % 2;

    // print out binary array
    for (digit = digit - 1; digit >=0; digit--)
        printf("%i", binary[digit]);

    printf("\n");
    return 0;
}