11.2. Base Classes and Derived Classes
Figure 11.1 lists several simple examples of base classes and derived classes. Base classes tend to be more general and derived classes tend to be more specific.
Because every derived-class object is an object of its base class, and one base class can have many derived classes, the set of objects represented by a base class typically is larger than the set of objects represented by any of its derived classes. For example, the base class
Vehicle represents all vehicles, including cars, trucks, boats, airplanes, bicycles and so on. By contrast, derived class
Car represents ...