How to round amount so its $0.00 without trailing?

Question

Here is my current program where it asks the user to input the item they're buying and the original price. The program will take a random percent off (between 5-75) and then give the user the new total price including a .07 tax added. The code is working great just that I'm not sure how to get the price amount to round to $0.00 and not have trailing numbers which ends up affecting the coins/dollars that the cash register would give in change. Any ideas? Thanks!

import java.util.Scanner;
import java.lang.Math;
import java.math.*;
import java.util.Random;

//declaring variables for methods
class Main
{
    Scanner scan = new Scanner(System.in); 
    //random variable for while loop
    int k=1;
    //other variables
    String name;
    double taxRate = 0.07; 
    int dollars, quarters, dimes, nickels, cent, discountPercentage;
    double discount, salePrice, tax, totalPrice, money, change, originalPrice, cents;


  //method to run entire program
  public void runProgram()
  { 
    //make sure to create program including a while loop
    while (k<2)
    {
      //here it explains the calculations and gets the user input of the item and original price of it
      System.out.println("As part of a store promotion, each customer is given a random percent off");
      System.out.println("Please enter the name of the item you plan to purchase: ");
      name = scan.nextLine();
      System.out.println("Enter the original price of that item: "); 
      originalPrice = scan.nextDouble();
      scan.nextLine();

      //here is where the user input is being calculated
      discountPercentage = getDiscount();
      discount = calculateDiscount(originalPrice, discountPercentage);
      salePrice = calculateSalePrice(originalPrice, discount);
      tax = calculateTax(salePrice); 
      totalPrice = calculateTotalPrice(salePrice, tax); 

      //print to user all the new calculations of item price
      System.out.println("The original price of the item is: " + originalPrice); 
      System.out.println("The discount percent on the item is: " + discountPercentage + "%");
      System.out.println("The new sale price of the item is: " + salePrice);
      System.out.println("The tax of the item is: " + tax);
      System.out.println("Now, the new total price of the item including the discount and tax is: " + totalPrice); 

      //this part will figure out how much money the user is giving the cashier and how much change needs to be given
      System.out.println("How much money are you giving to the cashier?");
      money = scan.nextDouble();
      scan.nextLine(); 
      change = solveChange(money, totalPrice);
      System.out.println("The change you will be given back is: " + change);
      convertChange(change);
      System.out.println("\n");
    }
  }

  //method for getting random discount for the item
  public int getDiscount()
  {
    //discount can only be in multiples in 5 ranging from 5-75, and all the variables for this method
    int multiple = 5;
    int discountStart = 5;
    int discountEnd = 75;
    int calculateDiscountStart;
    int calculateDiscountEnd;

    calculateDiscountStart = discountStart / multiple;
    calculateDiscountEnd = discountEnd / multiple;
    
    //random generator for the discount
    discountPercentage = new Random().nextInt(1 + calculateDiscountEnd - calculateDiscountStart) + calculateDiscountStart; 

    return discountPercentage * multiple;
  }

  //method for calculating the discount percent that is applied to original price of item
  public double calculateDiscount(double originalPrice, int discountPercentage)
  {
    discount = originalPrice * discountPercentage / 100;
    return discount;
  }

  //method to calculate the price with the discount applied to the item
  public double calculateSalePrice(double originalPrice, double discount)
  {
    salePrice = originalPrice - discount;
    return salePrice; 
  }

  //method to calculate the tax 
  public double calculateTax(double salePrice)
  {
    tax = salePrice * taxRate;
    return tax;
  }

  //method that will calculate the overall price including tax (adding previous methods together)
  public double calculateTotalPrice(double salePrice, double tax)
  {
    totalPrice = salePrice + tax; 
    return totalPrice;
  }

  //method that takes user input of how much money giving and calculating how much change they need
  public double solveChange(double money, double totalPrice)
  {
    change = money - totalPrice; 
    //int dollars = change/1; 
    return change;
  }

  //method to convert the change the user needs to dollars, quarters, etc
  public double convertChange(double change)
  {
    cents = change*100; 
    dollars = (int)cents/100; 
    quarters = (int)(cents % 100)/25; 
    dimes = (int)((cents%100)%25)/10;
    nickels = (int)(((cents%100)%25)%10)/5; 
    cent = (int)((((cents%100)%25)%10)%5); 
    //printing out the amount of change to the user
    System.out.println("Amount of change in Dollars is: " + dollars);
    System.out.println("Amount of change in Quarters is: " + quarters);
    System.out.println("Amount of change in Nickels is: " + nickels);
    System.out.println("Amount of change in Dimes is: " + dimes);
    System.out.println("Amount of change in Cents is: " + cent);
    return change;
  }

  //main method using static 
  public static void main(String[] args) {
    Main prog = new Main();
    prog.runProgram();
  }
}

Answer 1

What you usually do in real world programs that involve money: you use an int that is the total amount of pennies. So $ 1.99 = 199 int.