Updated Cash Machine Using JOptionPane & While Loops

Mainclass

import javax.swing.*;


public class Mainclass {
   
    public static void main(String[] args){
        int periodCounter = 0;
        double purchaseCost = 0;
        double cash = 0;
        String purchaseAmount = "";
        String amountGiven = "";
        boolean running = true;
        while (running) {
            periodCounter=0;
        purchaseAmount=JOptionPane.showInputDialog("Enter the purchase amount asked for by tender: ");

    for (int i = 0; i < purchaseAmount.length(); i++) {
        char buffer = purchaseAmount.charAt(i);
        if (buffer == '.') {
            periodCounter++;
            break;
        }
        if (periodCounter > 1) {
            JOptionPane.showMessageDialog(null, "Your bill must be a valid currency amount (this is not an IP address!)");
            running = true;

        }


    }

    try {
        purchaseCost = Double.parseDouble(purchaseAmount);
        running = false;
    } catch (NumberFormatException e) {
        JOptionPane.showMessageDialog(null, "The amount you entered was NOT a number :( " + purchaseAmount + " is NOT a valid currency value.");
        running = true;
    }
}

    String formattedCost1 = String.format("%.2f", purchaseCost);

    JOptionPane.showMessageDialog(null, "Your bill is " + formattedCost1);


running = true;


        while(running) {
            periodCounter=0;
       amountGiven = JOptionPane.showInputDialog("Enter the amount given");



            for (int i = 0; i < amountGiven.length(); i++) {
                char buffer = amountGiven.charAt(i);
                if (buffer == '.') {
                    periodCounter++;
                    break;
                }
                if (periodCounter > 1) {
                    JOptionPane.showMessageDialog(null, "Your bill must be a valid currency amount (this is not an IP address!)");
                    running = true;

                }


            }

            try {
                cash = Double.parseDouble(amountGiven);
                running = false;
            } catch (NumberFormatException e) {
                JOptionPane.showMessageDialog(null, "The amount you entered was NOT a number :( " + purchaseAmount + " is NOT a valid currency value.");
                running = true;
            }
        }
        String formattedCost2 = String.format("%.2f", cash);

        JOptionPane.showMessageDialog(null, "Your payment amount is " + formattedCost2);




        double purchaseAmountFinal= Double.parseDouble(purchaseAmount);
        double amountGivenToTendeFinal= Double.parseDouble(amountGiven);
        double change = amountGivenToTendeFinal - purchaseAmountFinal;
        double change2 = amountGivenToTendeFinal - purchaseAmountFinal;

        System.out.println(String.format( "%.2f", change ));
        System.out.println("You should receive: ");

        int singlesCounter = 0;
        int fivesCounter = 0;
        int tensCounter = 0;
        int twentyCounter = 0;
        int fiftyCounter = 0;
        int hundredCounter = 0;
        int pennyCounter = 0;
        int nickelCounter = 0;
        int dimeCounter = 0;
        int quarterCounter = 0;

        boolean subtracting = true;


        while (subtracting) {
            String buffer = String.format("%.2f", change);
            change = Double.parseDouble(buffer);
            if (change >= 100 && change - 100 >= 0) {
                change = change - 100;
                hundredCounter++;
            }

            if (change >= 50 && change - 50 >= 0 && change < 100) {
                change = change - 50;
                fiftyCounter++;
            }

            if (change >= 20 && change - 20 >= 0 && change < 100 && change < 50) {
                change = change - 20;
                twentyCounter++;
            }

            if (change >= 10 && change - 10 >= 0 && change < 20 && change < 50 && change < 100) {
                change = change - 10;
                tensCounter++;
            }
            if (change >= 5 && change - 5 >= 0 && change < 10 && change < 20 && change < 50 && change < 100) {
                change = change - 5;
                fivesCounter++;
            }
            if (change >= 1 && change - 1 >= 0 && change < 5 && change < 10 && change < 20 && change < 50 && change < 100) {
                change = change - 1;
                singlesCounter++;
            }

            if (change >= 0.25 && change - 0.25 >= 0 && change < 1 && change < 5 && change < 10 && change < 20 && change < 50 && change < 100) {
                change = change - 0.25;
                quarterCounter++;
            }

            if (change >= 0.10 && change - 0.10 >= 0 && change < 0.25 && change < 1 && change < 5 && change < 10 && change < 20 && change < 50 && change < 100) {
                change = change - 0.10;
                dimeCounter++;
            }
            if (change >= 0.05 && change - 0.05 >= 0 && change < 0.10 && change < 0.25 && change < 1 && change < 5 && change < 10 && change < 20 && change < 50 && change < 100) {
                change = change - 0.05;
                nickelCounter++;
            }
            if (change >= 0.01 && change - 0.01 >= 0 && change < 0.05 && change < 0.10 && change < 0.25 && change < 1 && change < 5 && change < 10 && change < 20 && change < 50 && change < 100) {
                change = change - 0.01;
                pennyCounter++;
            }
            if (change <= 0) {
                subtracting = false;
            }
        //
        }
        String message = "";

        if (hundredCounter == 1) {
            System.out.println("You should receive " + hundredCounter + " hundred dollar bill");
            message = message + "\n" + "You should receive " + hundredCounter + " hundred dollar bill";

        } else if (hundredCounter > 0) {
            System.out.println("You should receive " + hundredCounter + " hundred dollar bills");
            message = message + "\n" + "You should receive " + hundredCounter + " hundred dollar bills";
        }
        if (fiftyCounter == 1) {
            System.out.println("You should receive " + fiftyCounter + " fifty dollar bill");
            message = message + "\n" + "You should receive " + fiftyCounter + " fifty dollar bill";
        } else if (fiftyCounter > 0) {
            System.out.println("You should receive " + fiftyCounter + " fifty dollar bills");
            message = message + "\n" + "You should receive " + fiftyCounter + " fifty dollar bills";
        }
        if (twentyCounter == 1) {
            System.out.println("You should receive " + twentyCounter + " twenty dollar bill");
            message = message + "\n" + "You should receive " + twentyCounter + " twenty dollar bill";
        } else if (twentyCounter > 0) {
            System.out.println("You should receive " + twentyCounter + " twenty dollar bills");
            message = message + "\n" + "You should receive " + twentyCounter + " twenty dollar bills";
        }
        if (tensCounter == 1) {
            System.out.println("You should receive " + tensCounter + " ten dollar bill");
            message = message + "\n" + "You should receive " + tensCounter + " ten dollar bill";
        } else if (tensCounter > 0) {
            System.out.println("You should receive " + tensCounter + " ten dollar bills");
            message = message + "\n" + "You should receive " + tensCounter + " ten dollar bills";
        }
        if (fivesCounter == 1) {
            System.out.println("You should receive " + fivesCounter + " five dollar bill");
            message = message + "\n" + "You should receive " + fivesCounter + " five dollar bill";
        } else if (fivesCounter > 0) {
            System.out.println("You should receive " + fivesCounter + " five dollar bills");
            message = message + "\n" + "You should receive " + fivesCounter + " five dollar bills";
        }
        if (singlesCounter == 1) {
            System.out.println("You should receive " + singlesCounter + " single dollar bill");
            message = message + "\n" + "You should receive " + singlesCounter + " single dollar bill";
        } else if (singlesCounter > 0) {
            System.out.println("You should receive " + singlesCounter + " single dollar bills");
            message = message + "\n" + "You should receive " + singlesCounter + " single dollar bills";
        }
        if (quarterCounter == 1) {
            System.out.println("You should receive " + quarterCounter + " quarter");
            message = message + "\n" + "You should receive " + quarterCounter + " quarter";
        } else if (quarterCounter > 0) {
            System.out.println("You should receive " + quarterCounter + " quarters");
            message = message + "\n" + "You should receive " + quarterCounter + " quarters";
        }
        if (dimeCounter == 1) {
            System.out.println("You should receive " + dimeCounter + " dime");
            message = message + "\n" + "You should receive " + dimeCounter + " dime";
        } else if (dimeCounter > 0) {
            System.out.println("You should receive " + dimeCounter + " dimes");
            message = message + "\n" + "You should receive " + dimeCounter + " dimes";
        }
        if (nickelCounter == 1) {
            System.out.println("You should receive " + nickelCounter + " nickel");
            message = message + "\n" + "You should receive " + nickelCounter + " nickel";

        } else if (nickelCounter > 0) {
            System.out.println("You should receive " + nickelCounter + " nickels");
            message = message + "\n" + "You should receive " + nickelCounter + " nickels";
        }

        if (pennyCounter == 1) {
            System.out.println("You should receive " + pennyCounter + " penny");
            message = message + "\n" + "You should receive " + pennyCounter + " penny";

        } else if (pennyCounter > 0) {
            System.out.println("You should receive " + pennyCounter + " pennies");
            message = message + "\n" + "You should receive " + pennyCounter + " pennies";
        }


        JOptionPane.showMessageDialog(null, "Your change will be " + change2 + "\n" + message);



    }
}