21.8. Exercises: Inheritance

Work on these exercises in a new Visual Studio .Net Core console app. Name your solution Technology and make a project inside of it with the same name.

1. Class design: Create three classes inside your solution: Computer, Laptop, and SmartPhone. Before you start coding anything inside these classes, diagram how the three classes are going to be related to each other. Remember to add properties and methods to your diagram.

   1. For a parent class: add 3 fields, 2 methods, and a constructor.

   2. For a child class: add at least 1 additional field and 1 additional method.

   3. At least one of your fields should be either static, readonly, or a const.

2. Class implementation: Implement your design and add unit tests to a new TechnologyTests MSTest project.

   1. Add a new MSTest project to your solution.

   2. Try to add three MSTests tests per class.

3. Abstract class design: Consider the group of classes that you designed. Suppose you have a web program that uses these classes and you need to assign a unique ID to every object created from them. Each class should have an id field, and no two objects created from any of the classes may have the same value for id. Create an abstract class, AbstractEntity, that contains the behavior for assigning and accessing such a unique ID for each class that extends it. Add this class to your Technology project above, and add AbstractEntity to the class hierarchy in the correct place.