4000 虚函数的多态实现小解

#include<iostream>
using namespace std;
class base {
public:
virtual void print() {
cout << "base::print()" << endl;
}
virtual void goo() {
cout << "base::goo()" << endl;
}
};
class devired :public base {
public:
virtual void print() {
cout << "devired::print()" << endl;
}
virtual void go() {
cout << "devired::go()" << endl;
}
};
int main(void) {
devired b;
typedef void(*Fun)(void);
Fun pfun = NULL;
for (int i = 0; i < 3; i++)
{
pfun = (Fun)*((int*)*(int*)(&b)+i);
pfun();
}
system("pause");
}

#include<iostream>
using namespace std;
class point {
public:
virtual ~point() { cout << "~point()" << endl; }
virtual point& mult(float) = 0;
float x()const { return _x; }
virtual float y()const { return 0; }
virtual float z()const { return 0; }
protected:
point(float x = 0.0) {};
float _x;
};
class point2 :public point {
protected:
float _y;
public:
point2(float x = 0.0, float y = 0.0):point(x),_y(y){}
~point2() { cout << "~point2()" << endl; }
point2& mult(float);
float y()const { return _y; }
};
class point3 :public point2 {
protected:
float _z;
public:
point3(float x=0.0,float y=0.0,float z=0.0):point2(x,y),_z(z){}
~point3() { cout << "~point3()" << endl; }
point3&mult(float);
float z()const { return _z; }
};
void main(void) {
}