Pset1 Cash - Incorrect number of coins

Question

I've put together a solution to the problem set Cash using division. When I run the program, it returns incorrect number of coins for most of the cases, e.g. change 61 - 244 coins, change 0.80 - 14 coins but it returns a correct value for change 0.25 (1 coin). I would be grateful for any hints.

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

int main(void)
{
    int coins;
    float change;

    // Get user's input
    do
    {
        change = get_float("What is the change? ");
    }
    // Condition for the input
    while (change < 0);

// Round dollars to cents
change = round(change * 100);

// Calculate coins

{
    int q = change / 25;
    int d = (change - (25 * q)) / 10;
    int n = (change - ((25 * q) + (10 * d))) / 5;
    int p = (change - (25 * q) + (10 * d) + (5 * n)) / 1;
    coins = q + d + n + p;

printf("Number of used coins: %i\n", coins);
}
}

Answer 1

It's an efficient approach and you're on the right track! The problem is that it's calculating the total number of each type of coin required, but not accounting for the previous calculations.

Simply put, after accounting for the total number of quarters, the code needs to subtract the value of the quarters from the total before calculating dimes, and so on.

However, even after you fix this, you have another problem waiting in the wings, but one question/problem gets one answer. ;-)

If this answers your question, please click on the check mark to accept. Let's keep up on forum maintenance. ;-)