12. Object-Oriented Programming: Inheritance

In this chapter you'll learn:

To create classes by inheriting from existing classes.
How inheritance promotes software reuse.
The notions of base classes and derived classes and the relationships between them.
The protected member access specifier.
The use of constructors and destructors in inheritance hierarchies.
The order in which constructors and destructors are called in inheritance hierarchies.
The differences between public, protected and private inheritance.
The use of inheritance to customize existing software.

Say not you know another entirely, till you have divided an inheritance with him.

—Johann Kasper Lavater

This method is to define as the number of a class the class of all classes similar to the given class.

—Bertrand Russell

Good as it is to inherit a library, it is better to collect one.

—Augustine Birrell

Save base authority from others' books.

—William Shakespeare

12.1	Introduction
12.2	Base Classes and Derived Classes
12.3	`protected` Members
12.4	Relationship between Base Classes and Derived Classes
	12.4.1	Creating and Using a `CommissionEmployee` Class
	12.4.2	Creating a `BasePlusCommissionEmployee` Class Without Using Inheritance
	12.4.3	Creating a `CommissionEmployee–BasePlusCommissionEmployee` Inheritance Hierarchy
	12.4.4	`CommissionEmployeeBase–PlusCommissionEmployee` Inheritance Hierarchy Using `protected` Data
	12.4.5	`CommissionEmployee–BasePlusCommissionEmployee` Inheritance Hierarchy Using `private` Data
12.5	Constructors and Destructors in Derived Classes
12.6	`public, protected` and `private` Inheritance
12.7	Software Engineering with Inheritance
12.8	Wrap-Up