Introduction to OOP Chapter 23: Object Interconnections : next previous audio real text

Public, Subclass and Private Faces

We have several times noted that object have a public and private face - inheritance introduces a third alternative, the subclass face.

There are two types of clients for the class developer. These are user clients (those who use an instance of the class), and subclass clients (those who will subclass from the class).
Intro OOP, Chapter 23, Slide 19