C++ Video: Maintain is-a Relation for Public Ineritance

[boqian2000]

A good programming practice requires us to maintain is-a relation between base class and derived class. However, sometime things can become tricky. This video explains different pitfalls in maintaining the is-a relationship.

http://www.youtube.com/watch?v=97iK5r3zNug

[pogrady]

Im confused about this. I'm under the impression that overloaded functions with different arguments are differentiated by the compiler.