C++ Reference Wiki. Polymorphism. Before getting any deeper into this chapter, you should have a proper understanding of pointers and class inheritance.
If you are not really sure of the meaning of any of the following expressions, you should review the indicated sections: Pointers to base class.
Teach Yourself C++ in 21 Days. Bruce Eckel's Free Electronic Books. C++ Reference [C++ Reference] The Boost C++ Libraries.