Ivor Horton's Beginning Visual C++® 2010

Chapter 9. Class Inheritance and Virtual Functions

WHAT YOU WILL LEARN IN THIS CHAPTER:

• How inheritance fits into object-oriented programming

• Defining a new class in terms of an existing one

• How to use the protected keyword to define a new access specification for class members

• How a class can be a friend to another class

• How to use virtual functions

• Pure virtual functions

• Abstract classes

• When to use virtual destructors

In this chapter, you're going to look into a topic that lies at the heart of object-oriented programming (OOP): class inheritance. Simply put, inheritance is the means by which you can define a new class in terms of one you already have. This is fundamental to programming in C++, so it's important that you understand how inheritance works.

OBJECT-ORIENTED PROGRAMMING BASICS

As you have seen, a class is a data type that you define to suit your own application requirements. Classes in OOP also define the objects to which your program relates. You program the solution to a problem in terms of the objects that are specific to the problem, using operations that work directly with those objects. You can define a class to represent something abstract, such as a complex number, which is a mathematical concept, or a truck, which is decidedly physical (especially if you run into one on the highway). So, as well as being a data type, a class can also be a definition of a set of real-world objects of a particular kind, at least to the degree necessary to solve a given problem.

You can ...