In this exercise you will implement a shopping cart using the ArrayList class. T
ID: 3805542 • Letter: I
Question
In this exercise you will implement a shopping cart using the ArrayList class. The file Item.java contains the definition of a class named Item that models an item one would purchase (this class was used in an earlier lab). An item has a name, price, and quantity (the quantity purchased). The file Shop.java is an incomplete program that models shopping.
1. Complete Shop.java as follows:
a. Declare and instantiate a variable cart to be an empty ArrayList.
b. Fill in the statements in the loop to add an item to the cart and to print the cart contents (using the default toString in the ArrayList class). Comments in the code indicate where these statements go.
c. Compile your program and run it.
2. You should have observed two problems with using the default printing for the cart object: the output doesn’t look very good and the total price of the goods in the cart is not computed or printed.
Modify the program to correct these problems by replacing the print statement with a loop that does the following:
a. gets each item from the cart and prints the item
b. computes the total price of the items in the cart (you need to use the getPrice and getQuantity methods of the Item class). The total price should be printed after the loop.
3. Compile and run your program.
// ***************************************************************
// Shop.java
//
// Uses the Item class to create items and add them to a shopping
// cart stored in an ArrayList.
// ***************************************************************
import java.util.ArrayList;
import java.util.Scanner;
public class Shop {
public static void main (String[] args)
{
Item item;
String itemName;
double itemPrice;
int quantity;
Scanner scan = new Scanner(System.in);
String keepShopping = "y";
do
{
System.out.print ("Enter the name of the item: ");
itemName = scan.nextLine();
System.out.print ("Enter the unit price: ");
itemPrice = scan.nextDouble();
System.out.print ("Enter the quantity: ");
quantity = scan.nextInt();
// *** create a new item and add it to the cart 78
// *** print the contents of the cart object using println
System.out.print ("Continue shopping (y/n)? ");
keepShopping = scan.nextLine();
}
while (keepShopping.equals("y"));
}
}
Explanation / Answer
//Output has been formatted
Item.java
public class Item {
private String name;
private Double price;
private Integer quantity;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public Integer getQuantity() {
return quantity;
}
public void setQuantity(Integer quantity) {
this.quantity = quantity;
}
public Item() //Default Constructor
{
}
public Item(String name, Double price, Integer quantity) { //Constructor to initialize object with values passed as input
super();
this.name = name;
this.price = price;
this.quantity = quantity;
}
}
Shop.java
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Shop {
public static List<Item> cart = new ArrayList<Item>();
public static void main (String[] args)
{
Item item;
String itemName;
double itemPrice;
double total=0;
int quantity;
Scanner scan = new Scanner(System.in);
String keepShopping = "y";
do
{
System.out.println();
System.out.print ("Enter the name of the item: ");
itemName = scan.nextLine();
System.out.print ("Enter the unit price: ");
itemPrice = scan.nextDouble();scan.nextLine();
System.out.print ("Enter the quantity: ");
quantity = scan.nextInt();scan.nextLine();
// *** create a new item and add it to the cart 78
item = new Item(itemName,itemPrice,quantity);
Shop.cart.add(item);
// *** print the contents of the cart object using println
System.out.println();
System.out.println("Your shopping cart");
System.out.println("------------------");
for(Item cartItem: cart) //Iterating the cart to get items
{
System.out.println("Name: "+cartItem.getName());
System.out.println("Price: "+cartItem.getPrice());
System.out.println("Quantity: "+cartItem.getQuantity());
System.out.println();
total += getTotal(cartItem.getPrice(),cartItem.getQuantity());
}
System.out.print ("Continue shopping (y/n)? ");
keepShopping = scan.nextLine();
}
while (keepShopping.equals("y"));
System.out.println("__________________");
System.out.println("Total: "+total); //Get Total using price and quantity
scan.close();
}
private static Double getTotal(Double price, Integer quantity) {
return price*quantity;
}
}
Sample Output
Enter the name of the item: books
Enter the unit price: 100
Enter the quantity: 5
Your shopping cart
------------------
Name: books
Price: 100.0
Quantity: 5
Continue shopping (y/n)? y
Enter the name of the item: watches
Enter the unit price: 120
Enter the quantity: 6
Your shopping cart
------------------
Name: books
Price: 100.0
Quantity: 5
Name: watches
Price: 120.0
Quantity: 6
Continue shopping (y/n)? n
__________________
Total: 1720.0
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