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Java Java Objects (Retired) Delivering the MVP Defaulting Parameters

Derick Brown
Derick Brown
7,361 Points

Can someone help me with the Defaulting Parameters challenge?

This is my first time clicking the "Get Help" button from the challenge so if things are duplicated then I apologize as I'm not sure what gets posted when I click "Start Discussion" haha.

Anyway, I'm a little confused about this challenge as I'm not sure what's being asked of me.

The instructions are:

"So at your new Java job, you've written a brand new Shopping Cart system for the website. After some developers have used the objects you created for a while, they ask you to make it easier to add things to the cart.

Check out more instructions in Example.java. Once you implement their request, check your work, and you will pass the challenge."

I look at Example.java and they asked me to make the "following code work" so I proceeded to the next method. The next method tells me to uncomment the line so I do so. Then they tell me to "solve their request in ShoppingCart.java". So I move to ShoppingCart.java but I don't see a request.

Can someone help me with this challenge? Not really looking for an answer but an explanation of what they're asking me to do.

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 the line following this comment,
       after adding a new method 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. Please imagine
       lots and lots of code here. Don't repeat it. 
    */
  }
}
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;
  }
}

1 Answer

Simon Coates
Simon Coates
28,693 Points

The important part is:

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. Please imagine
       lots and lots of code here. Don't repeat it. 
    */
  }
  public void addItem(Product item) {
   addItem(item, 1);
  }
}
Derick Brown
Derick Brown
7,361 Points

Thanks for the help!

But can you please explain how you came to this conclusion? Like your thought process, steps you took, and what the directions were telling me so I know for future reference.

Simon Coates
Simon Coates
28,693 Points
    /* Uncomment the line following this comment,
       after adding a new method using method signatures,
       to solve their request in ShoppingCart.java
    */

This instruction is telling you to create a new method for the cart.addItem(dispenser); line. The signatures bit is in reference to the ability to create a method with the same name, provided the signature allows differentiation. If the method is called the same thing, and the number of parameters is different, then in java, i think you have to take this approach.

Derick Brown
Derick Brown
7,361 Points

Ahhh okay cool. I think I understand what's going on. I understand everything when I read it but I think I'm beginning to understand what they asked.

Thanks for everything!

Derick Brown
Derick Brown
7,361 Points

Ahhh okay cool. I think I understand what's going on. I understand everything when I read it but I think I'm beginning to understand what they asked.

Thanks for everything!