Introduction to OOP Chapter 8: Inheritance and Substitution: next previous audio real text

The is-a Rule

Our idealization of inheritance is captured in a simple rule-of-thumb.

Try forming the English sentences ``An A is-a B''. If it ``sounds right'' to your ear, then A can be made a subclass of B.

A dog is-a mammal, and therefore a dog inherits from mammal

A car is-a engine sounds wrong, and therefore inheritance is not natual. but a car has-a engine.

Intro OOP, Chapter 8, Slide 06