class animal
{
public:
	virtual void enjoy()
	{
		cout << "叫声。。。" << endl;
	}
};

class dog:public animal
{
public:
	void enjoy()
	{
		cout << "狗叫声。。。" << endl;
	}
};

class lady
{
public:
	animal *a;
	lady(animal *oo) :a(oo){}
	void jiao()
	{
		a->enjoy();
	}
};

//测试代码
animal *g=new dog();
	lady ll(g);
	ll.jiao();//输出“狗叫声。。。”

c++多态性的例子