该程序包含了c++中函数的多态性，是多态性的一个实例-The program contains a function, c polymorphism, is an example of polymorphism

虽然是一个小小的例子,却是基本上包括了C++多态的含义!是很好的学习材料-Although it is a small example, but it is basically a C polymorphism meaning! It is a good learning materials