gistfile1.txt

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

// quarters (25¢), dimes (10¢), nickels (5¢), and pennies (1¢)
// input of 0.41 yields output of 4
int coins = 0;

int get_change(int cents_remaining, int coin_value)
{
  coins += cents_remaining / coin_value;
  cents_remaining = cents_remaining % coin_value;
  return cents_remaining;
}

int main(void)
{
  int coin_values[] = {25, 10, 5, 1};

  float dollars = 0;

  do

  {
    dollars = get_float("Change owed:\n");
  }

  while (dollars < 0);
  // convert dollars to int to avoid imprecision
  int cents = round(dollars * 100);

  for (int i = 0; i < 4; i++)
  {
    cents = get_change(cents, coin_values[i]);
  }

  // return the number of coins needed
  printf("%i\n", coins);
  return 0;
}