Question

Write a program in Java that simulates a vending machine:

The vending machine sells three types of food: 1) Potato chips $1.25; 2) Cookies $0.85; 3) Candies $0.95. The program will prompt for the buyer to enter the amount in quarters (25 cents), dimes (10 cents), and nickels (5 cents). The program will then present a selection menu for the foods and prompt the buyer to enter the amount of quarters, dimes and nickels. The machine would then proceed to display the total amount inserted then the buyer will makes a selection. If the buyer selects a food that is sold out, the program will display a message and re-display the selection menu. If the buyer the equal amount of money to the food cost, the selected food will be dispensed, with a message "Please take a your (food)". If the amount is more than the cost, an appropriate amount of change (in quarter, dime or nickel) will be dispensed back to the buyer.

Every food is initialized with a fixed quantity. The quantity is reduced by one every time the food is dispensed. When the quantity of a food is 0, no more should be sold, with an error stating "Sold out. Please make another choice".

Note:

1 dollar = 4 quarters = 10 dimes = 20 nickels
1 dollar = 100 cents
1 quarter = 25 cents
1 dime = 10 cents
1 nickel = 5 cents

Answer 1

Food.java

public class Food {
private String name;
private double cost;
private int quantity;
  
public Food()
{
this.name = "";
this.cost = 0.0;
this.quantity = 0;
}

public Food(String name, double cost, int quantity) {
this.name = name;
this.cost = cost;
this.quantity = quantity;
}

public String getName() {
return name;
}

public double getCost() {
return cost;
}

public int getQuantity() {
return quantity;
}

public void setName(String name) {
this.name = name;
}

public void setCost(double cost) {
this.cost = cost;
}

public void setQuantity(int quantity) {
this.quantity = quantity;
}
}

VendingMachineApp.java (Driver class)

import java.util.ArrayList;
import java.util.Scanner;

public class VendingMachineApp {
  
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
ArrayList<Food> foods = loadFood();
int choice;
  
do
{
displayMenu(foods);
choice = Integer.parseInt(sc.nextLine().trim());
  
if(choice == 0)
{
System.out.println("\nThanks for using the Vending Machine.\nGoodbye!\n");
System.exit(0);
}
  
if(choice < 0 || choice > foods.size())
System.out.println("\nInvalid choice!\n");
else
{
if (foods.get(choice - 1).getQuantity() == 0)
{
System.out.println("Sold out. Please make another choice!\n");
break;
}
else
{
System.out.print("Enter number of quarters (1 quarter = 25 cents): ");
int nQuarters = Integer.parseInt(sc.nextLine().trim());
System.out.print("Enter number of dimes (1 dime = 10 cents): ");
int nDimes = Integer.parseInt(sc.nextLine().trim());
System.out.print("Enter number of nickels (1 nickel = 5 cents): ");
int nNickels = Integer.parseInt(sc.nextLine().trim());
int totalCents = (nQuarters * 25) + (nDimes * 10) + (nNickels * 5);
double dollars = ((double)totalCents / 100);
System.out.println("\nYou entered: $" + String.format("%.2f", dollars));

if(dollars < foods.get(choice - 1).getCost())
System.out.println("Insufficient price entered.\n");
else
{
System.out.println("Please take your " + foods.get(choice - 1).getName());
foods.get(choice - 1).setQuantity(foods.get(choice - 1).getQuantity() - 1);
if(dollars > foods.get(choice - 1).getCost())
{
System.out.print("Here's your change: ");
double change = dollars - foods.get(choice - 1).getCost();
double cents = (change * 100);
int quarters = (int)(cents / 25);
double rem = (cents % 25);
int dimes = (int)(rem / 10);
rem = (rem % 10);
int nickels = (int)(rem / 5);

System.out.println(quarters + " quarters, " + dimes + " dimes and " + nickels + " nickels.");
}
System.out.println();
}   
}
}
}while(choice != 0);
}
  
private static ArrayList<Food> loadFood()
{
ArrayList<Food> foods = new ArrayList<>();
foods.add(new Food("Potato chips", 1.25, 10));
foods.add(new Food("Cookies", 0.85, 13));
foods.add(new Food("Candies", 0.95, 10));
  
return foods;
}
  
private static void displayMenu(ArrayList<Food> foods)
{
System.out.println("Choose from below:");
int counter = 0;
for(Food food : foods)
{
System.out.println(++counter + ". " + food.getName() + " $" + food.getCost());
}
System.out.print("0. Exit\n"
+ "Enter your choice: ");
}
}

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