#include "iostream" 
using namespace std; 
class CBase{ 
  public: 
      virtual void xfn(int i){ 
          cout << "Base::xfn(int i)" << endl; //1 
      } 
      void yfn(float f){ 
          cout << "Base::yfn(float)" << endl; //2 
      } 
      void zfn(){ 
          cout << "Base::zfn()" << endl; //3 
      } 
}; 
class CDerived : public CBase{ 
  public: 
      void xfn(int i){ 
        cout << "Derived::xfn(int i)" << endl; //4 
      } 
      void yfn(int c){ 
        cout << "Derived:yfn(int c)" << endl; //5 
      } 
      void zfn(){ 
        cout << "Derived:zfn()" << endl; //6 
      } 
}; 
void main(){ 
    CDerived d; 
    CBase *pb = &d; 
    CDerived *pd = &d; 
    pb->xfn(5); //覆盖 
    pd->xfn(5); //直接调用 
 
    pb->yfn(3.14f); //直接调用 
    pd->yfn(3.14f); //隐藏 
 
    pb->zfn(); //直接调用 
    pd->zfn(); //隐藏 
}