greedy.c

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

int main(void)
{
    //declare variables
    float change;
    int coins, cents;

    //Get user input, must be non-negative.
    do
    {
        printf("O hai! How much change is owed?\n");
        change = get_float();
    }while (change <0);

    //convert into int and minimise floating point imprecision
    cents = (int)round(change*100);
    coins = 0;

    //Get how many 25c coins are needed, get the remainder via modulo
    coins += cents / 25;
    cents %=25;
    //Get how many 10c coins are needed, get the remainder via modulo
    coins+= cents / 10;
    cents %= 10;

    //Get how many 5c coins are needed, get the remainder via modulo
    coins += cents / 5;
    cents %= 5;

    //remainder coins are pennies
    coins += cents;

    //Print result
    printf("%i\n", coins);
    return 0;

}