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Java Java Objects (Retired) Delivering the MVP Defaulting Parameters

Sohaib Rashid
Sohaib Rashid
627 Points

help!

If anyone is familiar with this, your help would be highly appreciated! happy coding!

Example.java
public class Example {

  public static void main(String[] args) {
    ShoppingCart cart = new ShoppingCart();
    Product pez = new Product("Cherry PEZ refill (12 pieces)");
    cart.addItem(pez, 5);
    /* Since a quantity of 1 is such a common argument when adding a product to the cart,
     * your fellow developers have asked you to make the following code work, as well as keeping
     * the ability to add a product and a quantity.
     */
    Product dispenser = new Product("Yoda PEZ dispenser");
    // Uncomment this line after using method signatures to solve their request in ShoppingCart.java
    // cart.addItem(dispenser);
  }

}
ShoppingCart.java
public class ShoppingCart {

  public void addItem(Product item, int quantity) {
    System.out.printf("Adding %d of %s to the cart.%n", quantity, item.getName());
    /* Other code omitted for clarity */
  }
}
Product.java
public class Product {
  /* Other code omitted for clarity, but you could imagine
     it would store price, options like size and color
  */
  private String mName;

  public Product(String name) {
      mName = name;
  }

  public String getName() {
      return mName;
  }
}

2 Answers

Dan Johnson
Dan Johnson
40,533 Points

You can have methods with the same name if they have differing arguments (referred to as overloading). This challenge wants you to have an "addItem" method that doesn't require a quantity. You can do this by:

  1. Creating another method in ShoppingCart with the same method signature as addItem, but without the quantity argument.
  2. Calling the other "addItem" method from within the one you just created with a default quantity (1 in this case).
  3. Uncommenting the call to the method in Example.java

Example.java has a line of code that is commented out

    cart.addItem(dispenser);

If all you do is uncomment this line and check your work, you get a compiler error. We need to write a second addItem method that only takes one argument, rather than two.

So, in ShoppingCart.java, we can copy and paste the existing addItem method, but remove the second argument. We also need to change what is printed, because we know that we are "Adding 1 of" the item to the cart.