Sams Teach Yourself C++ in 24 Hours, fifth edition

Hour 20. Using Special Classes, Functions, and Pointers

What You’ll Learn in This Hour:

• What static member variables and static member functions are

• How to use static member variables and static member functions

• What friend functions and friend classes are

• How to use friend functions to solve special problems

• How to use pointers to member functions

Static Member Data

Until now, you have probably thought of the data in each object as unique to that object and not shared among objects in a class. For example, if you have five Cat objects, each has its own age, weight, and other data. The age of one does not affect the age of another.

Sometimes, however, you’ll want to keep track of information shared among the many objects of a class. ...