Định nghĩa lại các thành viên lớp cơ sở trong một lớp dẫn xuất

http://employ.h
//dinh nghi alop employ
#ifndef EMPLOY_H
#define EMPLOY_H

class Employee
{
private:
   char *ho;
   char *ten;
public:
   Employee(const char *h, const char *t);
   void Print() const;
   ~Employee();
};
#endif

http://employ.cpp
//dinh nghia cac ham thanh vien cua employee
 #include <string.h>
 #include <iostream.h>
 #include <assert.h>
 #include "employ.h"

 Employee::Employee(const char *h, const char *t)
 {
   ho = new char[ strlen(h) + 1 ];
   assert(ho != 0);
   strcpy(ho, h);
   ten = new char[ strlen(t) + 1 ];
   assert(ten != 0);
   strcpy(ten, t);
 }

 void Employee::Print() const
 {
   cout << ho << ' ' << ten;
 }

 Employee::~Employee()
 {
   delete [] ho;
   delete [] ten;
 }

//Dinh nghia gio lam viec cua moi cong nhan
#ifndef HOURLY_H
#define HOURLY_H

#include "employ.h"

class GioLV : public Employee
{
private:
   float LuongMoiGio; //Tien luong trong moi gio
   float GioMoiTuan;  //So gio lam viec trong moi tuan
public:
   GioLV(const char *ho, const char *ten, float SoGio, float SoTien);
   float TraLuong() const; // Tinh toan va tra luong
   void Print() const;    // Dinh nghia lai ham Print() cua lop co so
};

#endif

http://gio.cpp
//dinh nghia cac ham thanh vien cua lop GioLV
#include <iostream.h>
#include <iomanip.h>
#include "gio.h"

GioLV::GioLV(const char *ho, const char *ten, float SoGio, float SoTien) : Employee(ho, ten)
{
   GioMoiTuan = SoGio;
   LuongMoiGio = SoTien;
}

float GioLV::TraLuong() const
{
   return LuongMoiGio*GioMoiTuan;
}

void GioLV::Print() const
{
   //cout<<"Gio lam viec: "<<endl<<Employee::Print();
   cout<<"So tien: "<<setiosflags(ios::showpoint)<<setprecision(2)<<TraLuong()<<endl;
}

http://thucthi1.cpp
#include <iostream.h>
#include "gio.h"

void main()
{
   GioLV H("Au","Dung",40.0, 8.5);
   H.Print();
   cout<<endl<<"Nhan cong: "<<endl;
   H.Employee::Print();
}