C++使程序兼容

我目前有一个main.cc和一个database.cc文件，它们工作得很好，但我的main.cc文件与要测试的文件不匹配。我试过转换它，但它不断抛出错误，我没有时间破坏我的整个代码并重新开始。

这是我的数据库.cc文件：

#include<list>
#include<algorithm>
#include<iostream>
#include<string>
#include<fstream>
#ifndef passenger_h
#define passenger_h
 using std::string;
 using std::cin;
 using std::cout;
 using std::list;
 using std::endl;
class Passenger {
public:
    Passenger() {}
    Passenger(string, string, string);
    bool operator==(const Passenger&) const;
    bool operator<(const Passenger&) const;
    void print(std::ostream& os);
private:
    string fname, lname, destination;
};
class Flightlist {
public:
    int menu();
    void read_from_file(string);
    void insert(Passenger p);
    void remove(Passenger p);
    bool check_reservation(Passenger p);
    void display_list();
    void save_to_file(string);
private:
    list<Passenger> flist;
};
#endif

Passenger::Passenger(string first, string last, string dest)
{
    fname = first;
    lname = last;
    destination = dest;
}
bool Passenger::operator==(const Passenger& p) const
{
    return fname == p.fname && lname == p.lname;
}
bool Passenger::operator<(const Passenger& p) const
{
    return fname < p.fname || (fname == p.fname && lname < p.lname);
}
void Passenger::print(std::ostream& os)
{
    os << fname << ' ' << lname << ' ' << destination << 'n';
}
int Flightlist::menu()
{
    int option;
    cout << endl;
    cout << "Enter one of the following options:" << endl;
    cout << "1. load reservations from file:" << endl;
    cout << "2. reserve a ticket" << endl;
    cout << "3. cancel a reservation" << endl;
    cout << "4. check reservation" << endl;
    cout << "5. display passenger list" << endl; 
    cout << "6. save passenger list" << endl;
    cout << "7. exit" << endl << endl;
    cin >> option;
    cin.get();
    return option;
}
void Flightlist::read_from_file(string filename)
{
    string fname, lname, destination;
    std::ifstream input(filename.c_str());
    while (input >> fname >> lname >> destination) 
    {                   
        flist.push_back(Passenger(fname, lname, destination));
    }
    input.close();
}
void Flightlist::insert(Passenger p)
{
    flist.push_back(p);
}
void Flightlist::remove(Passenger p)
{
    flist.remove(p);
}
bool Flightlist::check_reservation(Passenger p)
{
    list<Passenger>::iterator i1, i2;
    i1 = flist.begin();
    i2 = flist.end();
    return flist.end() != find(flist.begin(), flist.end(), p);
}
void Flightlist::display_list()
{
    flist.sort();
    list<Passenger>::iterator i1, i2;
    i1 = flist.begin();
    i2 = flist.end();
    for ( ; i1 != i2; ++i1) {
        i1->print(cout);
    }
}
void Flightlist::save_to_file(string filename)
{
    flist.sort();
    list<Passenger>::iterator i1, i2;
    i1 = flist.begin();
    i2 = flist.end();
    std::ofstream output(filename.c_str());
    for ( ; i1 != i2; ++i1) {
        i1->print(output);
    }
    output.close();
}

这是我当前的main.cc文件，它与上面的程序完美配合：

#include "database.cc"
    int main()
    {   
        Flightlist flight_list;
        string fname, lname, destination;
    while (true) 
    {
        switch (flight_list.menu())
        {
            case 1: 
                {
                    flight_list.read_from_file("ticket_reservations.dat");
                    break;
                }
            case 2: 
                {
                    cout << "first name of passenger:" << endl; 
                    cin >> fname;
                    cout << "last name of passenger" << endl;
                    cin >> lname;
                    cout << "destination of passenger" << endl;
                    cin >> destination;
                    flight_list.insert(Passenger(fname, lname, destination));
                    break;
                }
            case 3: 
                {
                    cout << "first name of passenger:" << endl; 
                    cin >> fname;
                    cout << "last name of passenger" << endl;
                    cin >> lname;
                    cout << "destination of passenger" << endl;
                    cin >> destination;
                    flight_list.remove(Passenger(fname, lname, destination));
                    break;
                }
            case 4: 
                {
                    cout << "first name of passenger:" << endl; 
                    cin >> fname;
                    cout << "last name of passenger" << endl;
                    cin >> lname;
                    cout << "destination of passenger" << endl;
                    cin >> destination;
                    if (flight_list.check_reservation(Passenger(fname, lname, destination)))
                        cout << "this passenger has a ticket reservation" << endl;
                    else
                        cout << "this passenger does not have a ticket reservation" << endl;
                    break;
                }
            case 5: 
                {
                    flight_list.display_list();
                    break;
                }
            case 6: 
                {
                    flight_list.save_to_file("ticket_reservations.dat");
                }
                break;

            case 7:
                return 0;
        }
    }
    return 0;
}

这是我的程序将要测试的main.cc文件，因此我需要将代码转换为兼容

#include "database.cc"
int main()
{
    list<Passenger> flight_list;
    string first_name, last_name, destination;
    while (true) 
    {
        switch (menu())
        {
            case 1: 
                {
                    read_from_file(flight_list, "ticket_reservations.dat");
                    break;
                }
            case 2: 
                {
                    cout << "name of passenger:" << endl; 
                    cin >> first_name >> last_name;
                    cout << "destination:" << endl;
                    cin.ignore();
                    getline(cin, destination);
                    insert(flight_list, first_name, last_name, destination);
                    break;
                }
            case 3: 
                {
                    cout << "name of passenger:" << endl;
                    cin >> first_name >> last_name;
                    remove(flight_list, first_name, last_name);
                    break;
                }
            case 4: 
                {
                    cout << "name of passenger:" << endl;
                    cin >> first_name >> last_name;
                    if (check_reservation(flight_list, first_name, last_name))
                        cout << "this passenger has a ticket reservation" << endl;
                    else
                        cout << "this passenger does not have a ticket reservation" << endl;
                    break;
                }
            case 5: 
                {
                    display_list(flight_list);
                    break;
                }
            case 6: 
                {
                    save_to_file(flight_list, "ticket_reservations.dat");
                }
                break;
            case 7:
                return 0;
        }
    }
    return 0;
}

我对大量的代码深表歉意，但我迫切需要帮助。非常感谢。