C++多态的实现条件

#include <iostream>
class Person{
public:
	virtual void say(){
		std::cout<<"person"<<std::endl;
	}
};
class Student:public Person{
public:
	void say(){
		std::cout<<"student"<<std::endl;
	}
};
int main(){
	Person per;
	Student stud;
	per.say();
	stud.say();
	//传递对象
	per = stud;
	per.say();
	//指针
	Person *pPtr = &stud;
	pPtr->say();
	//引用
	Person &pRef = stud;
	pRef.say();
}