我正在尝试创建一个库系统。我有一个名为3.cpp的源文件，有几个类名为Game.h、DVD.h、Book.h、Library.h和Media.h。

我正在3.cpp中创建一个名为lib的对象，并试图从Game类访问lib对象。我该怎么做？我在Mac操作系统上使用Eclipse。

3.cpp源文件是：

#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <string>
#include "Library.h" // include header of Library class
#include "Game.h" // include header of Game class
#include "DVD.h" // include header of DVD class
#include "Book.h" // include header of Book class
using namespace std;
int main(){
    Library lib;
    while( 1 ){
        char mainSelect;
        char gameOption, name[30], platform[30], copies[10];
        char dvdOption, director[30];
        char bookOption, author[30];
        char mainMenu;
        // Read user selection
        cin.getline( name, 80);
        mainSelect = name[0];
        // Switch statement to select between the options
        switch (mainSelect){
           case '1':
              break;
           case '2':
               break;
           case '3':
               break;
           case '4':
               exit(0);
               break;
           case '5':
               cout << "Invalid selection!" << endl;
               system("pause");
               break;
        }
        if (mainSelect == '1'){
           cin.getline( name, 80);
           dvdOption = name[0];
        switch (dvdOption){
           case '1':
              cout << "Enter Name of DVD: ";
              cin.getline( name, 80);
              cout << "Enter Director of DVD: ";
              cin.getline(director, 80);
              cout << "Enter no of copies: ";
              cin.getline(copies, 80);
              lib.insertDVD( name, director, atoi(copies));
              break;
           case '2':
              cout << "Enter Name of DVD:n";
              cin.getline(name, 80);
              lib.deleteDVD(name);
              break;
           case '3':
              cout << "Enter Name of DVD:n";
              cin.getline(name, 80);
              DVD *item;
              item = lib.searchDVD( name );
              if( item != NULL){
                cout << "DVD foundn" << item->name << endl << item->director << endl << item->copies << endl;
              }
              else
              cout << "DVD not foundn";
              break;
           case '4':
              break;
           case '5':
              exit(0);
              break;
           case '6':
              cout << "Invalid selection!" << endl;
              system("pause");
              break;
        }
        }
        else if (mainSelect == '2'){
          "I need to add a method here to call the GameMenu method from the Game class."

    return 0;
}

游戏类代码为：

#ifndef GAME_H_
#define GAME_H_
#include "Media.h"
#include "Library.h"
using namespace std;
class Game : public Media{
public:
    char platform[45];
    char gameOption, name[30], platform[30], copies[10];
    void GameMenu(){
cout << "****************************************************" << endl;
           cout << "*******************  Game Menu  ********************" << endl;
           cout << "****************************************************" << endl;
           cout << "*                                                  *" << endl;
           cout << "* PROGRAM          DESCRIPTION                     *" << endl;
           cout << "* ------------------------------------------------ *" << endl;
           cout << "*                                                  *" << endl;
           cout << "*   1              Add a new Game                  *" << endl;
           cout << "*                                                  *" << endl;
           cout << "*   2              Delete a Game                   *" << endl;
           cout << "*                                                  *" << endl;
           cout << "*   3              Search for a Game               *" << endl;
           cout << "*                                                  *" << endl;
           cout << "*   4              Return to the previous Menu     *" << endl;
           cout << "*                                                  *" << endl;
           cout << "*   5              EXIT                            *" << endl;
           cout << "*                                                  *" << endl;
           cout << "* ------------------------------------------------ *" << endl;
           cout << "*                                                  *" << endl;
           cout << "****************************************************" << endl;
            cin.getline( name, 80);
            gameOption = name[0];
        switch (gameOption){
           case '1':
             cout << "Enter Name of Game: ";
             cin.getline( name, 80);
             cout << "Enter game platform: ";
             cin.getline(platform, 80);
             cout << "Enter no of copies: ";
             cin.getline(copies, 80);
             lib.insertGame( name, platform, atoi(copies));
             break;
           case '2':
             cout << "Enter Name of Game:n";
             cin.getline(name, 80);
             lib.deleteGame(name);
             break;
           case '3':
             cout << "Enter Name of Game:n";
             cin.getline(name, 80);
             Game *item;
             item = lib.searchGame( name );
             if( item != NULL){
             cout << "Game foundn" << item->name << endl << item->platform << endl << item->copies << endl;
             }
             else
             cout << "Game not foundn";
             break;
             case '4':
             exit(0);
             break;
           case '5':
             cout << "Invalid selection!" << endl;
             system("pause");
             break;
        }
    }
};

#endif // end of "#ifndef" block

在尝试访问Game类中创建的lib对象时，我也遇到了一些错误。我得到的错误是：

1. Use of undefined identifier lib.
2. Method insertGame could not be resolved.
3. Method deleteGame could not be resolved.