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Java Java Objects (Retired) Delivering the MVP Defaulting Parameters

Posted by cam
cam
7,468 Points

Code Challenge: How to deal with different number of arguments?

I'm just not getting it. I'm trying to have a method before the original method that scans the length of the second argument to determine if it is present, so that a default value can be put in. I'm wondering how to get around the fact that methods cannot have the same classes of arguments.How is it possible to give a Product and a int to the original method, if I can't use Product and int? Code below. Can someone please give me a hint?

public class ShoppingCart {
  public Product addItem(Product test1, int test2) {
    if(String.valueOf(test2).length()==0) {
    return addItem(test1,1);
    } else {
      return addItem(test1,test2);
    }
  }
  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 */
  }
}
cam
cam
7,468 Points 
public class ShoppingCart { 
public Product addItem(Product test1, int test2) { 
if(String.valueOf(test2).length()==0) { 
return addItem(test1,1); } 
else { 
return addItem(test1,test2); 
} 
} 
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 */ } 
}

2 Answers

Micah Kline
Micah Kline
17,831 Points

Methods can not support the same param values but can have different ones its the Object type that matters not the variable name. In the main Example.java it wants you to uncomment the line cart.addItem(dispenser);

So create a method that supports just that and assume that quatity is 1. Example Below..

public void addItem(Product item){
   // call the other add Item with a defaul quatity of one like
   addItem(item, 1); // this calls the method with the Products, int signature
}

public void addItem(Product item, int quantity){
// code omited
}
cam
cam
7,468 Points

Thanks for the response!

Jess Sanders
Jess Sanders
12,086 Points
Jess Sanders
Jess Sanders
12,086 Points

Here's my simplest explanation of what's going on in the 'defaulting parameters' code challenge:

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" of the item to the cart.