Object Oriented Programming with C++, Second Edition

9.3 PUBLIC DERIVATION

Now consider a practical application. We want to use a computer as a digital clock! For any digital clock, time is the basic building block. It also shows AM/PM. We have already defined and used a class time0. How can we use it to our advantage? Principle of inheritance comes into the picture. We can define a new class called clock based on the previously defined class time0. A new class clock will inherit properties of old class time0.

With public derivation, a typical declaration will look as follows:

class Clock : public Time0

The class definition does the following:

1. Class clock is defined.
2. It is derived from an existing class Time0.
3. The derivation is public. In this example, class Time0 is the base class and class ...