geeksforgeeks-047-派生类中的虚函数

#include<iostream>
 
using namespace std;
 
class A {
  public:
    virtual void ()
    { cout<<"n A::fun() called ";}
};
 
class B: public A {
  public:
    void ()
    { cout<<"n B::fun() called "; }     
};
 
class C: public B {
  public:
    void ()
    { cout<<"n C::fun() called "; }     
};
 
int main()
{
   C c; 
   B *b = &c; // A pointer of type B* pointing to c
   b->fun();  // this line prints "C::fun() called"
   getchar();
   return 0;
}