greedy_modulo_version.c

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

int main(void)
{
    // prompt user for an amount of change
    float user_input;
    int change, num_of_coins;
    
    do
    {
        printf("Enter the amount of change you want back: ");
        user_input = get_float();
    }
    while(user_input < 0);
    
    change = round(user_input*100);
    
    // keep track of coin used
    num_of_coins = 0;
    
    // always use the largest coin possible
    
    // modulo math version is tricky
    
    num_of_coins += change / 25;
    change %= 25;
    
    num_of_coins += change / 10;
    change %= 10;
    
    num_of_coins += change / 5;
    change %= 5;
    
    num_of_coins += change / 1;
    change %= 1;
    
    // print the final number of coins
    
    printf("You entered:\t%.2f\n", user_input);
    
    printf("least coins possible:\t%d\n", num_of_coins);
    
}