#include <iostream> using namespace std; class P{ public: P * m_p; P(){ this->m_p=this; } virtual void Intro(){ cout<<"this is P"<<endl; } }; class S:public P{ public : virtual void Intro(){ cout<<"this is S"<<endl; } }; S s; int main(){ s.Intro(); s.m_p->Intro(); return 0; }