Java class to break down change into coins?

Question

I am working on a java assignment where you enter the price of an object and the amount a theoretical customer handed you for the item. Then the program returns how much you owe them, and breaks it down into dollars, quarters, dimes, nickles, and pennies that you should give them.

Basically here's what it would look like when it runs

What was the purchase price? (exclude the decimal in calculation if it helps you)
$98.50
How much money did you pay with? (exclude the decimal)
$100.00
The purchase price was $98.50
You payed $100.0
You received $1.50 in change.
0 one hundred dollar bill(s)
0 fifty dollar bill(s)
0 twenty dollar bill(s)
0 ten dollar bill(s)
0 five dollar bill(s)
1 one dollar bill(s)
2 quarter(s)
0 dime(s)
0 nickel(s)
0 penny/pennies

I understand most of it, but I cant seem to wrap my mind around the breakdown of the change handed back. Here's my code so far, but if someone could show me how to break down the change.

import java.util.*;
public class ChangeTendered {

    public static void main(String[] args){

        Scanner scan = new Scanner(System.in);

        System.out.println("Enter the purchase price: ");
        double price = scan.nextDouble();
        System.out.println("Enter the amount payed: ");
        double ammountPayed = scan.nextDouble();

        double changeDue = ammountPayed - price;

        int dollars = (int)changeDue;

        System.out.println("Return"+ dollars+ "Dollars");

        scan.close();
    }

}

On a side note, I just cast the changeDue to an int in order to chop off the decimal and get the dollars due, if that caused any confusion.

Answer 1

import java.math.BigDecimal;
import java.math.MathContext;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Scanner;

public class ChangeTenderedWorking {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter the purchase price: ");
        BigDecimal price = scan.nextBigDecimal();
        System.out.println("Enter the amount paid: ");
        BigDecimal amountPayed = scan.nextBigDecimal();
        Map<Denomination, Integer> changeDue = getDenomination(amountPayed, price);

        for(Denomination denomination : changeDue.keySet()) {
            System.out.println("Return " + denomination + " bill(s) : "+ changeDue.get(denomination));
        }
        scan.close();
    }

    public static Map<Denomination, Integer> getDenomination(BigDecimal amountPayed, BigDecimal price) {
        BigDecimal change = amountPayed.subtract(price);
        System.out.println("Return change -- "+ change);
        Map<Denomination, Integer> changeReturn = new LinkedHashMap<Denomination, Integer>();
        for(Denomination denomination : Denomination.values()) {

            BigDecimal[] values = change.divideAndRemainder(denomination.value, MathContext.DECIMAL32);
            if(!values[0].equals(BigDecimal.valueOf(0.0)) && !values[1].equals(BigDecimal.valueOf(0.0))) {
                changeReturn.put(denomination, values[0].intValue());
                change = values [1];
            }

        }
        return changeReturn;
    }

    enum Denomination {
        HUNDRED(BigDecimal.valueOf(100)),
        FIFTY(BigDecimal.valueOf(50)),
        TWENTY(BigDecimal.valueOf(20)),
        TEN(BigDecimal.valueOf(10)),
        FIVE(BigDecimal.valueOf(5)),
        TWO(BigDecimal.valueOf(2)),
        ONE(BigDecimal.valueOf(1)),
        QUARTER(BigDecimal.valueOf(0.25)),
        DIME(BigDecimal.valueOf(0.10)),
        NICKEL(BigDecimal.valueOf(0.5)),
        PENNY(BigDecimal.valueOf(0.1));

        private BigDecimal value;

        Denomination(BigDecimal value) {
            this.value = value;
        }
    }
}

Answer 2

From what I can understand, you need to break the returned money into different bills: 100, 50, 20, 10, 5 ... etc.

I think you can use 'division' to solve the problem in Java. The following pseudo code is how you might solve the problem:

//For example:
double changeDue = 15.5;
double moneyLeft = changeDue;

int oneHundred = moneyLeft  / 100;
moneyLeft -= oneHundred * 100;

int fifty = moneyLeft  / 50;
moneyLeft -= fifty*50 ;

...

//Just remember to 'floor' the result when divided by a double value:

int quarter = Math.floor( moneyLeft / 0.25);
moneyLeft -= quarter * 0.25 ;
...//Until your minimum requirement.

//Then print out your results.

Hope it helps.

Answer 3

Here is an initial approach

    int change = (int)(Math.ceil(changeDue*100));
    int dollars = Math.round((int)change/100);
    change=change%100;
    int quarters = Math.round((int)change/25);
    change=change%25;
    int dimes = Math.round((int)change/10);
    change=change%10;
    int nickels = Math.round((int)change/5);
    change=change%5;
    int pennies = Math.round((int)change/1);

    System.out.println("Dollars: " + dollars);
    System.out.println("Quarters: " + quarters);
    System.out.println("Dimes: " + dimes);
    System.out.println("Nickels: " + nickels);
    System.out.println("Pennies: " + pennies);

You can add more code to the do it for currency notes as well.

Answer 4

What I did was convert it to a string then do a decimal split to separate the change and dollars.

import java.util.Scanner;
import java.text.DecimalFormat;
public class register 
{
  public static void main(String[] args)
  {
    DecimalFormat decimalFormat = new DecimalFormat("0.00");

    Scanner kb = new Scanner(System.in);
    System.out.print("How much does this item cose? -> ");
    double cost = kb.nextDouble();
    System.out.print("How many will be purcased? -> ");
    double quanity = kb.nextDouble();
    double subtotal = (cost * quanity);
    double tax = (subtotal * .06);
    double total = (subtotal + tax);
    System.out.print("How much money has been tendered? -> ");
    double tendered = kb.nextDouble();
            double change = (tendered - total);

        int dollars = (int)change;
        int twenties = dollars / 20;
        int dollars1 = dollars % 20;
        int tens = dollars1 / 10;
        int dollars2 = dollars % 10;
        int fives = dollars2 / 5;
        int dollars3 = dollars % 5;
        int ones = dollars3;

        String moneyString = decimalFormat.format(change);
        String changeString = Double.toString(change); 
        String[] parts = moneyString.split("\\.");
        String part2 = parts[1]; 
        double cents5 = Double.parseDouble(part2);

        int cents = (int)cents5;
        int quarters = cents / 25;
        int cents1 = cents % 25;
        int dimes = cents1 / 10;
        int cents2 = cents % 10;
        int nickels = cents2 / 5;
        int cents3 = cents % 5;
        int pennies = cents3;

        System.out.println("Cost: " + "$" + decimalFormat.format(cost));
        System.out.println("Quanity: " + quanity);
        System.out.println("Subtotal: " + "$" + decimalFormat.format(subtotal));
        System.out.println("Tax: " + "$" + decimalFormat.format(tax));
        System.out.println("Total: " + "$" + decimalFormat.format(total));
        System.out.println("Tendered: " + "$" + decimalFormat.format(tendered));
        System.out.println("Change: " + "$" + moneyString);


        System.out.println(twenties + " Twenties");
        System.out.println(tens + " Tens");
        System.out.println(fives + " Fives");
        System.out.println(ones + " Ones");
        System.out.println(quarters + " Quarters");
        System.out.println(dimes + " Dimes");
        System.out.println(nickels + " Nickels");
        System.out.println(pennies + " Pennies");

  }
}