Software Engineering and Computer Games

4.3. Encapsulation, inheritance, and polymorphism

The technique of putting data and methods inside a single object is called encapsulation. The two other words most commonly used when talking about OO are inheritance and polymorphism.

The idea behind inheritance is that if you already have a class that’s almost like something you need, its a good idea to define a new class that is a child class of the existing class, recoding or overriding some of the new class methods so that they behave differently from the old class. We can draw a picture of inheritance as in Figure 4.4.

Figure 4.4. A class and a subclass

When an inherited method calls the ...