I am having trouble figuring out what to do with the error I receive. This is my Shopping Cart project

Question

In this exercise you will complete a class that implements a shopping cart as an array of items. The file Item.java contains the definition of a class named Item that models an item one would purchase. An item has a name, price, and quantity (the quantity purchased). The file ShoppingCart.java implements the shopping cart as an array of Item objects.

1. Complete the ShoppingCart class by doing the following: a. Declare an instance variable cart to be an array of Items and instantiate cart in the constructor to be an array holding capacity Items. b. Fill in the code for the increaseSize method. Your code should be similar to that in Listing 7.8 of the text but instead of doubling the size just increase it by 3 elements. c. Fill in the code for the addToCart method. This method should add the item to the cart and update the totalPrice instance variable (note this variable takes into account the quantity). d. Compile your class.

2. Write a program that simulates shopping. The program should have a loop that continues as long as the user wants to shop. Each time through the loop read in the name, price, and quantity of the item the user wants to add to the cart. After adding an item to the cart, the cart contents should be printed. After the loop print a “Please pay ...” message with the total price of the items in the cart.

   package Shopping;
   
   import java.text.NumberFormat;
   
   public class Item
   {
       private String name;
       private double price;
       private int quantity;
       // ----------------------------------------------------- --
       // Create a new item with the given attributes.
       // ----------------------------------------------------- --
       public Item (String itemName, double itemPrice, int numPurchased)
       {
           name = itemName;
           price = itemPrice;
           quantity = numPurchased;
       }
       // ----------------------------------------------------- --
       // Return a string with the information about the item
       // ----------------------------------------------------- --
       public String toString ()
       {
           NumberFormat fmt = NumberFormat.getCurrencyInstance();
           return (name + "\t" + fmt.format(price) + "\t" + quantity + "\t"
                   + fmt.format(price*quantity));
       }
       // -----------------------------------------------
       // Returns the unit price of the item
       // -----------------------------------------------
   
       public double getPrice()
       {
           return price;
       }
       // -----------------------------------------------
       // Returns the name of the item
       // -----------------------------------------------
       public String getName()
       {
           return name;
       }
       // -----------------------------------------------
       // Returns the quantity of the item
       // -----------------------------------------------
       public int getQuantity()
       {
           return quantity;
       }
   }
   
   
   
   package Shopping;
   
   import Shopping.Item;
   
   import java.text.NumberFormat;
   
   public class ShoppingCart
   {
       private int itemCount; // total number of items in the cart
       private double totalPrice; // total price of items in the cart
       private int capacity; // current cart capacity
       Item[] cart; // declare an instance variable cart for an array of Item
   
   
       // ---------------------------------------------------------
       // Creates an empty shopping cart with a capacity of 5 items.
       // ---------------------------------------------------------
   
       public ShoppingCart()
       {
           capacity = 5;
           itemCount = 0;
           totalPrice = 0.0;
           cart = new Item[capacity];
   
       }
   
       // -----------------------------------------------------
       // Adds an item to the shopping cart.
       // -----------------------------------------------------
       public void addToCart(String itemName, double price, int quantity)
       {
           if (itemCount > 5)
           {
               System.out.println("Now the shopping cart is full.");
           }
           else
           {
               addToCart(itemName, price, quantity);
               totalPrice = totalPrice + (price *  quantity);
           }
           itemCount = itemCount+1;
       }
   
   
       // -----------------------------------------------------
       // Returns the contents of the cart together with
       // summary information.
       // -----------------------------------------------------
   
       public String toString()
       {
           NumberFormat fmt = NumberFormat.getCurrencyInstance();
           String contents = "\nShopping Cart\n";
           contents += "\nItem\t\tUnit Price\tQuantity\tTotal\n";
           for (int i = 0; i < itemCount; i++)
               contents += cart[i].toString() + "\n";
           contents += "\nTotal Price: " + fmt.format(totalPrice);
           contents += "\n";
           return contents;
       }
       // -----------------------------------------------------
       // Increases the capacity of the shopping cart by 3
       // -----------------------------------------------------
       private void increaseSize()
       {
           capacity = capacity + 3;
       }
   }
   

Exception in thread "main" java.lang.StackOverflowError at Shopping.ShoppingCart.addToCart(ShoppingCart.java:39) IS THE ERROR I KEEP RECEIVING

Answer 1

You keep calling the addToCart() method in your 'else' statement in the same method, and it's not doing anything (just keeps calling the same block of code and then terminates with a StackOverflowError). I'm pretty sure you meant to add a created Item to the array:

else {
    cart[itemCount] = new Item(itemName, price, quantity);
    totalPrice += (price *  quantity);
    itemCount++; // Same thing as itemCount = itemCount + 1
}

You also need to modify your 'if' condition in addToCart(), because right now it attept to place an item in the array slot capacity, but your array index stops at capacity - 1. To fix it:

if(itemCount > capacity - 1){