Chapter 4

Defining C++ Classes

• Defining a class

• Creating a class instance

• Accessing class members

• Encapsulation

• Constructors and destructors

• Inline member functions

• The this pointer

• Static class members

           This Chapter introduces C++ Classes. When you define a class, you create a new data type, which you can use much like on of the built - in C++ data types. A class, however, contains code as well as data. A class allows you to encapsulate all a window on the screen, a figure that the program draws, a device connected to a techniques for creating and using individual classes. In the next chapter, you'll learn how to define and use hierachies of related classes.

• Defining a Class

          A C++ class is somewhat similar to a standard C structure, though the features of C++ classes go far beyond those provided by C structures. To understand C++ classes, it's useful to start by considering how structure are used in the C language.

         A C structure allows you to group a set of related data items. As a simple example, if your C program draws a rectangle on the screen, you might find it convenient to store the coodinates of the rectangle within a structure  defined as follows : 

         Struct Rectangle 

        {

            int   Left;

            int   Top;

            int   Right;

            int   Bottom;

          };
              You could then define a function for drawing the rectangle, as in the following example.
             Void Draw Rectangle (Struct Rectangle *Rect)