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Java Java Objects (Retired) Delivering the MVP Defaulting Parameters

Posted by Mark John
Mark John
Courses Plus Student 771 Points

Java challenge question help

This is the question ===>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....plz i need u suggestions.thanx

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;
  }
}
John Miller
John Miller
4,007 Points

Hi Mark John, this one gave me pause too. The instructions are the comments in Example.java. When stumped I like to break things down into simple steps. The first comment (instruction) tells us - 

/* 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.
 */

Thats a lot of text to basically say, duplicate the existing method 'addItem' in ShoppingCart.java to accept only the 'Product item' when the quantity is defaulted to '1'.

Something similar to:

//New method we create
   public void addItem(Product item) {
         int mQuantity = 1; // Default value

         //Then call the existing method :)
         addItem(item, mQuantity);
   }

//Exiting method which we call
   public void addItem(Product item, int quantity) {
         System.out.printf("Adding %d of %s to the cart.\n", quantity, item.getName());

    //Remember to then uncomment the call to card.addItem(dispenser); in Example.java
}

I hope this helps. Please look at it and think it through to make sure it makes sense to you.

3 Answers

John Miller
John Miller
4,007 Points 
public class ShoppingCart {

   public void addItem(Product item) {
         int mQuantity = 1; // Default value

         //Then call the existing method
         addItem(item, mQuantity);
   }

  public void addItem(Product item, int quantity) {
         System.out.printf("Adding %d of %s to the cart.\n", quantity, item.getName());
   }

}

Sorry, I'm not real familiar with Markdown and messed up the formatting in the original post

Gianluca Belardinelli
Gianluca Belardinelli
886 Points
Gianluca Belardinelli
Gianluca Belardinelli
886 Points

I think the question is not well written. This is what I make to make it working

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 */
  }

     public void addItem(Product item)
    {
             addItem(item,1);
    }
}
Mark John
PLUS
Mark John
Courses Plus Student 771 Points
Mark John
Mark John
Courses Plus Student 771 Points

tanx everyone! your answers were helpful.i appreciate the help