虚函数实现多态性 代码参考

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 class pet
 6 {
 7     public:
 8         virtual void speak(){cout<<"how does a pet speak?"<<endl;}
 9 };
10 
11 class cat:public pet
12 {
13     public:
14         void speak(){cout<<"miao!miao!"<<endl;}
15 };
16 
17 class dog:public pet
18 {
19     public:
20         void speak(){cout<<"wang!wang!"<<endl;}
21 };
22 
23 int main()
24 {
25     pet one, *p1,*p2,*p3;
26     cat two;
27     dog three;
28     p1=&one;
29     p2=&two;
30     p3=&three;
31     p1->speak();
32     p2->speak();
33     p3->speak();
34     return 0;
35 }