Ivor Horton's Beginning Visual C++ 2012

OBJECT-ORIENTED PROGRAMMING BASICS

As you have seen, a class is a data type that you define to suit your own application requirements. Classes in OOP also define the objects to which your program relates. You program the solution to a problem in terms of the objects that are specific to the problem, using operations that work directly with those objects. You can define a class to represent something abstract, such as a complex number, which is a mathematical concept, or a truck, which is decidedly physical (especially if you run into one on the highway). So, as well as being a data type, a class can also be a definition of a set of real-world objects of a particular kind, at least to the degree necessary to solve a given problem.

You can think of a class as defining the characteristics of a particular group of things that are specified by a common set of parameters and share a common set of operations that may be performed on them. The operations that you can apply to objects of a given class type are defined by the class interface, which corresponds to the functions contained in the public section of the class definition. The CBox class that you used in the previous chapter is a good example — it defined a box in terms of its dimensions plus a set of public functions that you could apply to CBox objects to solve a problem.

Of course, there are many different kinds of boxes in the real world: there are cartons, coffins, candy boxes, and cereal boxes, to name but a few, and you ...