I'm really confused on this method signatures challenge

Question

Hi there,
I am working on this method signatures challenge, where I have to pass in a method in example.java and the create an overloaded one in shoppingcart.java. I am really stuck and have tried most things I can think of. If you could include some code that would be very helpful. Thanks for the help!
```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. 
    */
public void addItem(Product item) {
   this.addItem(item, 1);
}
  }
}
```
```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;
  }
}
```

Steve Hunter · Accepted Answer

Hi Gabriel, 
Have a look through this (https://teamtreehouse.com/community/how-can-i-add-a-new-product-instead-o-1-product-to-the-cart-in-this-challenge) post, as it contains what I'll type here in a minute! 
Steve.

Steve Hunter · Answer

Hi Gabriel, 
The current functionality in the addItem method means you need to send two parameters into the method; a product and a quantity. The challenge says that the quantity of 1 is very common so, rather than having to type out the number 1 every time a single product is needed, it should be possible to add one product by omitting that fgure. Sort of a default setting - if there's no quantity defined, just add one. 
You can use the existing method to do this, but first you need to override the method signature to cater for the single parameter.  You do that by just declaring the new signature with the single parameter. So your first step needs you to add this to the ShoppingKart file:
java
  public void addItem(Product item) {
    /// we'll add code in a minute
  }

Inside this method, we don't need to do much. We don't want to replicate the whole of the original addItem() method as there's lts of stuff in there that we don't see (and don't want to!!). So inside our new method, we can use the old method, but add the original extra parameter as a number 1.
So the completed new method looks like:
java
  public void addItem(Product item) {
    addItem(item, 1);
  }

You then need to uncomment a line of code, and you should get through the challenge. 
Steve.

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Gabriel E

Gabriel E

I'm really confused on this method signatures challenge

2 Answers

Steve Hunter

Steve Hunter

Steve Hunter

Steve Hunter

Steve Hunter

Steve Hunter