#include<iostream>

using namespace std;

class Shape{

public:

virtual void Areo(){

cout<<"Shape::Areo()"<<endl;

}

};

class Circle:public Shape{

//解开注释，证明覆盖存在

// virtual void Areo()

// {

// cout<<"Circle::Areo"<<endl;

// }

};

int main()

{

Shape s;

cout<<sizeof(s)<<endl;

cout<<&s<<endl;

unsigned int **p=(unsigned int**)&s;

cout<<**p<<endl;

void (*sss)()=(void (*)())(**p);

sss();

cout<<"_______________________"<<endl;

Circle c;

cout<<sizeof(c)<<endl;

cout<<&c<<endl;

unsigned int **q=(unsigned int**)&c;

cout<<**q<<endl;

void (*ccc)()=(void (*)())(**q);

ccc();

return 0;

}

运行结果：

4

0x28fe8c

4317648

Shape::Areo()

_______________________

4

0x28fe88

4317648

Shape::Areo()

--------------------------------