ShoppingCart.java

// **********************************************************************
//   ShoppingCart.java//
//   Represents a shopping cart as an array of items
// **********************************************************************
import java.text.NumberFormat;
public class ShoppingCart {
    private int itemCount;
    private Item[] cart;
    // total number of items in the cart
    private double totalPrice;
    // total price of items in the cart
    private int capacity;
    // current cart capacity
    // -----------------------------------------------------------
    //  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 == cart.length) {
            increaseSize();
        }
        cart[itemCount] = new Item(itemName, price, quantity);
        totalPrice += price * quantity;
        itemCount++;
    }
    // -------------------------------------------------------
    //  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() {
        Item[] temp = new Item[cart.length + 3];
        for (int i = 0; i < cart.length; i++) {
            temp[i] = cart[i];
        }
        cart = temp;
    }
}