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Java Java Objects (Retired) Delivering the MVP Defaulting Parameters

Alex Rodriguez
seal-mask
.a{fill-rule:evenodd;}techdegree
Alex Rodriguez
Front End Web Development Techdegree Student 20,810 Points

Problem with code challenge

I keep getting this error : Hmmm, seems like you shouldn't repeat yourself, why don't you try calling the original addItem method with the default parameter of 1.

I am not sure what I am doing wrong.

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 */
     }
public void addItem(Product item){ System.out.printf("Adding 1 of %s to the cart.%n", item.getName()); } 

}
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;
  }
}

4 Answers

Craig Dennis
STAFF
Craig Dennis
Treehouse Teacher

Sigh...I can't seem to stop y'all from hacking. SPOILER

The idea of method overloading is this:

// Original method
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 */
}

// New method
public void addItem(Product item) {
    // Call the original, just pass in the default
    addItem(item, 1);
}
Victor Learned
Victor Learned
6,976 Points

Your code is correct but because in ShoppingCart.java you changed the output to something the grading software doesn't like it's failing you. Change it to the following and it will work.

System.out.printf("Adding %d of %s to the cart.%n", 1,  item.getName()); } 
Alex Rodriguez
seal-mask
.a{fill-rule:evenodd;}techdegree
Alex Rodriguez
Front End Web Development Techdegree Student 20,810 Points

Thank you, it worked. I am just having a hard time understanding %d. I know its for numbers like %s to strings, but where did the 1 come from? I thought that the 1 needed to be store in a variable then called.

Alex Rodriguez
seal-mask
.a{fill-rule:evenodd;}techdegree
Alex Rodriguez
Front End Web Development Techdegree Student 20,810 Points

Thank you, it worked. I am just having a hard time understanding %d. I know its for numbers like %s to strings, but where did the 1 come from? I thought that the 1 needed to be store in a variable then called.