Objects As Parameters and Return Values

Objects As Parameters And Return Values

The goal for this exercise is to make sure that you can both pass objects to methods, and return objects from methods, as well as continuing to write programs that are composed of decoupled classes.

For this exercise, you should continue to work with the TelevisionHandler and Television classes that were defined in the previous exercises. Other than implementing the basic methods on the Television class, it should not be necessary to complete those other exercises in order to complete this one.

What you need to do for this exercise:

1.  Add a new method to the TelevisionHandler class, named PickMoreExpensiveTV. PickMoreExpensiveTV is given (as parameters) 2 Television objects, figures out which one costs more (using the getter methods on the Television class), and returns that one. This method must be created by you, from scratch, if it hasn't been already.

a.  If the two Televisions have the same price, then you must return the first parameter.

b.  If the method is given one null parameter and one non-null parameter, then the method should return the non-null parameter. If both parameters are null, then the method should return null.

i.  This public method should never crash, no matter what values are passed in as parameters.

c.  Because the prior exercise, implementing the CreateATV method, creates and returns a new Television object, some students get the impression that all methods that return an object must create that object. This exercise is set up like this not only to emphasize both passing objects into and back out of methods, but also to emphasize that not all methods that return an object needs to instantiate (to create) that object.

2.  You should fully understand how to make use of the above method in particular, and of passing objects into and returning an object from a method, in general.

a.  There is a Objects_As_Parameters_And_Return_Value.RunExercise method that you can use to test your work.

b.  You must have your Objects_As_Parameters_And_Return_Value.RunExercise method create two Television objects that you’ll be comparing. Next, call the PickMoreExpensiveTV method, saving that more expensive TV into a third local variable, named moreExpensiveTV. Finally, call the TelevisionHandler.PrintMyTV method on each of the Television objects, and then announce which Television is more expensive, and then print that one.