Java-找零的纸币和硬币数量最少

Question

I have to do an assignment for my class that allows the user to key in two amounts - the first should be the total sale amount and the next would be the amount of change handed to the cashier. The program needs to calculate the change needed and tell the cashier how many of each monetary amount to return to the customer using the least number of bills and coins. Using $20, 10, 5, 1 and 0.25, 0.10, 0.05, and 0.01. I also need to include a while loop to make sure the cashier is given an amount greater than the amount due.

I have the following so far, but don't know where to go from here:

public class Change {

public static void main(String[] args) {

    Scanner input = new Scanner(System.in);
    //Enter sale amount less than $100
    System.out.println("Enter the sale amount: ");
    double price = input.nextDouble();
    //Enter amount of money handed to cashier less than $100
    System.out.println("Enter the amount of money handed to the cashier: ");
    double payment = input.nextDouble();
    double difference = payment - price;

    int num20 = (int)(difference / 20);
    System.out.println("num20 = " + num20);
    difference = difference % 20;
    System.out.println("difference = " + difference);

    int num10 = (int)(difference / 10);
    System.out.println("num20 = " + num10);
    difference = difference % 10;
    System.out.println("difference = " + difference);

    int numQtr = (int)(difference / .25);
    System.out.println("numqtr = " + numQtr);

    int numDime = (int)(difference / .10);
    System.out.println("numDime = " + numDime);     

}

Answer 1

Use the mod operator and division to find values at each step

29 % 20 -> 9
(int) (29 / 20) -> 1

9 % 10 -> 9
(int) (9 / 10) -> 0

please note that casting the result of a division to an integer will truncate the returned value to a whole number.