How to fix broken math in java program for getting change back

Question

My group and I are working on a somewhat simple program in Java that will take two different prices and calculate the change between it. A problem we are having that we can't seem to find/fix is that the math for the change is completely incorrect.

NOTE: We are using Repl.it

import java.util.Scanner;

class Main {
    public static void main(String[] args) {

        String input, cost, payment, change;
        String bills, coins;
        int dollarsOwed, dollarsPaid;

        Scanner money = new Scanner(System.in);

        System.out.println(" ");
        System.out.println(
                "Please enter the amount of the purcahse followed by the amount of a payment, separated by a comma.");

        System.out.println(" ");
        System.out.print("Amount of Purchase, Amount of Payment: ");
        input = money.nextLine();

        int a = input.indexOf(",");
        payment = input.substring(a + 1);
        cost = input.substring(0, a);
        double x = Double.parseDouble(cost);
        double y = Double.parseDouble(payment);

        dollarsOwed = (int) x;
        double centsOwed1 = (x - dollarsOwed) * 100;
        centsOwed1 = Math.round(centsOwed1);
        int centsOwed = (int) centsOwed1;

        dollarsPaid = (int) y;
        double centsPaid1 = (y - dollarsPaid) * 100;
        centsPaid1 = Math.round(centsPaid1);
        int centsPaid = (int) centsPaid1;

        String billsString = billsChange(dollarsOwed, dollarsPaid);
        String centsString = coinsChange(centsOwed, centsPaid);
        printBills(billsString);
        printCoins(centsString);

    }

    static String billsChange(int dollarsOwed, int dollarsPaid) {
        int dollarsReturned;
        int thisDenomination = 0;
        String retString = "";

        dollarsReturned = dollarsPaid - dollarsOwed;

        // Calculate $100 bills needed
        thisDenomination = dollarsReturned / 100;
        dollarsReturned -= thisDenomination * 100;
        retString += Integer.toString(thisDenomination);

        // Calculate $50 bills needed
        thisDenomination = dollarsReturned / 50;
        dollarsReturned -= thisDenomination * 50;
        retString += Integer.toString(thisDenomination);

        // Calculate $20 bills needed
        thisDenomination = dollarsReturned / 20;
        dollarsReturned -= thisDenomination * 20;
        retString += Integer.toString(thisDenomination);

        // Calculate $10 bills needed
        thisDenomination = dollarsReturned / 10;
        dollarsReturned -= thisDenomination * 10;
        retString += Integer.toString(thisDenomination);

        // Calculate $5 bills needed
        thisDenomination = dollarsReturned / 5;
        dollarsReturned -= thisDenomination * 5;
        retString += Integer.toString(thisDenomination);

        // Calculate $1 bills needed
        retString += Integer.toString(dollarsReturned);

        return (retString);

    }

    static String coinsChange(int centsOwed, int centsPaid) {
        int changeReturned;
        int thisDenomination = 0;
        String retString = "";

        changeReturned = centsPaid - centsOwed;

        // Calculate quarters(25¢) needed
        thisDenomination = changeReturned / 25;
        changeReturned -= thisDenomination * 25;
        retString += Integer.toString(thisDenomination);

        // Calculate dimes(10¢) needed
        thisDenomination = changeReturned / 10;
        changeReturned -= thisDenomination * 10;
        retString += Integer.toString(thisDenomination);

        // Calculate nickels(5¢) needed
        thisDenomination = changeReturned / 5;
        changeReturned -= thisDenomination * 5;
        retString += Integer.toString(thisDenomination);

        // Calculate pennies(1¢) needed
        retString += Integer.toString(changeReturned);

        return (retString);
    }

    static void printBills(String bills) {
        String printString = "";
        String billName = "";
        for (int i = 0; i <= 5; i++) {
            if (bills.charAt(i) != '0') {
                switch (i) {
                case 0:
                    billName = "$100";
                    break;
                case 1:
                    billName = "$50";
                    break;
                case 2:
                    billName = "$20";
                    break;
                case 3:
                    billName = "$10";
                    break;
                case 4:
                    billName = "$5";
                    break;
                case 5:
                    billName = "$1";
                    break;
                }
                printString += (bills.charAt(i) + "-" + billName + " ");
            }
        }
        System.out.print(printString);
    }

    static void printCoins(String coins) {
        String printString = "";
        String coinName = "";
        for (int i = 0; i <= 3; i++) {
            if (coins.charAt(i) != '0') {
                switch (i) {
                case 0:
                    coinName = "$0.25";
                    break;
                case 1:
                    coinName = "$0.10";
                    break;
                case 2:
                    coinName = "$0.05";
                    break;
                case 3:
                    coinName = "$0.01";
                    break;
                }
                printString += (coins.charAt(i) + "-" + coinName + " ");
            }
        }
        System.out.print(printString);
    }
}

Example:

User Input: 11.33,15.00

Expected Output: 3-$1 2-$0.25 1-$0.10 1-$0.05 2-$0.01 (CORRECT)

Actual Output: 4-$1 --$0.25 1-$0.10 --$0.01 (INCORRECT)

Answer 1

I think the issue is because you are using int's as your datatype, when u subtract ints datatype then decimal places are dropped therefore if you do 15-11.33 you get 4 because the.33 is dropped in int datatype.

int dollarsOwed, int dollarsPaid   
dollarsReturned = dollarsPaid - dollarsOwed;

change there variables to double, or float and that should fix it.