The Object-Oriented Thought Process, Fourth Edition

What Exactly Is a Class?

In short, a class is a blueprint for an object. When you instantiate an object, you use a class as the basis for how the object is built. In fact, trying to explain classes and objects is really a chicken-and-egg dilemma. It is difficult to describe a class without using the term object and visa versa. For example, a specific individual bike is an object. However, someone had to have created the blueprints (that is, the class) to build the bike. In OO software, unlike the chicken-and-egg dilemma, we do know what comes first—the class. An object cannot be instantiated without a class. Thus, many of the concepts in this section are similar to those presented earlier in the chapter, especially when we talk about attributes ...