shiti3_4_4.cpp

为C++学习者

#include<iostream.h>
class A
{
public:
	virtual void f(){cout<<"Base cass A."<<endl;}
};
class B:public A
{
public:
	virtual void f(){cout<<"Derived cass B."<<endl;}
};
void fun(A &x)
{
	x.f();
}
void main()
{
	A a;
	B b;
	fun(a);
	fun(b);
}