In this module, we look at how to implement the is-a relationships we modeled earlier in our UML diagrams through the use of Inheritance. Inheritance provides additional ways to abstract code in taxonomies where base classes share code with specialized versions of the classes. We will add a discussion about exceptions work in Visual Basic now that we can discuss inheritance.

In this module, we extend our implementation of the is-a relationships so that our code can work with specializations of a class without knowing the specifics of the specialization. This level of abstraction is known as polymorphism. Polymorphism provides additional ways to abstract code to work on objects in a taxonomy.

In this module, we continue our deep dive into the implementation of the is-a relationships. In our early work, we developed taxonomies for the purposes of abstraction. Now we want to think about the situation where a class could be in several taxonomies. This level of abstraction is known as an interface in modern programming. Interfaces provide signatures but not implementation so that we can use Polymorphism on objects that fall in multiple taxonomies.