7. Mastering Inheritance and Composition

Inheritance and composition play major roles in the design of object-oriented (OO) systems. In fact, many of the most difficult and interesting design decisions come down to deciding between inheritance and composition.

Both inheritance and composition are mechanisms for reuse. Inheritance, as its name implies, involves inheriting attributes and behaviors from other classes. In this case, there is a true parent/child relationship. The child (or subclass) inherits directly from the parent (or superclass).