纯虚函数应用

#include "iostream"using namespace std;class Animal{public:    virtual void cry() = 0;};class Mouse : public Animal{public:    void cry()    {        cout<<"吱！"<
    
     cry();    Mouse m1;    p=&m1;    p->cry();    Cat c1;    p=&c1;    p->cry();    Dog d1;    p=&d1;    p->cry();    return 0;}