C++虚函数与C++虚函数表

这个问题被勾起来的原因是听到师兄面试又被提到。本来知道这玩意，但还是想实践检验一下加深理解。

1）上酸菜：

　　类是创建对象的模子！

#include <iostream>
using namespace std;

class root
{
protected:
    int id;
public:
    root()
    {
        id = 1;
    }
    virtual void say()
    {
        cout << "i am the root" << endl;
    }
    virtual void move()
    {
        cout << "i can move here and there" << endl;
    }
};

class leaf: public root
{
protected:
    int color;
public:
    leaf()
    {
        id = 2;
        color = 999;
    }
    void say()
    {
        cout << "I am the leaf" << endl;
    }
};
int main(int argc, char* argv[])
{
    root r;
    r.say();

    leaf l;
    l.say();

    root* p;
    p = new leaf();
    //p->say();
    //p->move();

    return 0;
}