Visual Basic 2005 for Programmers: Deitel Developer Series, Second Edition

Chapter 11. Object-Oriented Programming: Polymorphism

One Ring to rule them all, One Ring to find them, One Ring to bring them all and in the darkness bind them.

—J. R. R. Tolkien

General propositions do not decide concrete cases.

—Oliver Wendell Holmes

A philosopher of imposing stature doesn’t think in a vacuum. Even his most abstract ideas are, to some extent, conditioned by what is or is not known in the time when he lives.

—Alfred North Whitehead

Why art thou cast down, O my soul?

—Psalms 42:5

Objectives

In this chapter you will learn: What polymorphism is. To use overridden methods to effect polymorphism. To distinguish between abstract and concrete classes. To declare abstract methods to create abstract classes. How polymorphism makes ...