#include <iostream>
using namespace std;
class Father
{
  public:
    Father() { A(); }
     void virtual A() { cout<<"Father::A()"<<endl; }
     void B() { cout<<"Father::B()"<<endl; A();}
};
class Son : public Father
{
  public:
    void A() { cout<<"Son::A()"<<endl; }
    void B() { cout<<"Son::B()"<<endl; }
};
int main()
{
  Father f;//father::A
  Son s;//father::a!!!
  Father *pf=&s;
  pf->A();
 
  pf->B();
  s.A();//son::a
  s.B();//son::b
}
        
关注到如果虚函数是在Father()的构造函数中,是不体现虚特性的,而在其它地方是体现的,比如关注void B()中的A()