多态性是面向对象程序设计的关键技术之一。若程序设计语言不支持多态性，不能称为面向对象的语言。利用多态性技术，可以调用同一个函数名的函数，实现完全不同的功能。

-Polymorphism of object-oriented programming is one of key technologies. If the programming language does not support polymorphism can not be called object-oriented language. Using polymorphism, you can call a function with a function name to achieve a completely different function.