sdut 6-2 多态性与虚函数

#include <iostream>

using namespace std;

class Pet
{
public :
    virtual void speak()//定义虚函数
    {
        cout<<"How does a pet speak ?"<<endl;
    }
};

class Cat: public Pet
{
public :
    void speak ()
    {
        cout <<"I am a cat,My name is Tom My sound is miao!miao!"<<endl;
    }
};

class Dog : public Pet
{
public :
    void speak()
    {
        cout<<"I am a dog,My name is Snoppy My sound is wang!wang!"<<endl;
    }
};

int main()
{
    Pet p, *t;//定义Pet类对象的指针t
    Cat c;
    Dog d;

    t = &p;//t指针指向p
    t->speak();//调用p.speak函数

    t = &c;//t指针指向c
    t->speak();//调用c.speak函数

    t = &d;//t指针指向d
    t->speak();//调用d.speak函数

    return 0;
}