C ++使程序兼容

Question

I currently have a main.cc and a database.cc file that work perfectly, but my main.cc file does not match the one that it is going to be tested with. I've tried to convert it but it keeps throwing errors and I don't have the time to break my whole code and start again.

This is my database.cc file:

#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();
}

This is my current main.cc file, which works perfectly with the above program:

#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;
}

This is the main.cc file that my program will be tested with, and therefore what I need to convert my code to be compatible with:

#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;
}

I strongly apologise for the large amount of code, but I desperately need help with this. Thank you!

Answer 1

Your functions are not working because you have never defined them as general functions; they are class function members.

You need to iterate through your list and call the class member - I'm not going to rewrite all your code, but here's an illustration:

list<MyClass> MyList;
// ... your list is populated here ..
for(auto iter=MyList.begin(); iter!=MyList.end(); ++iter) {
    // ... decide what to do here ...
    *iter->MyMethod(argument1,argument2)
    // ... etc ...
}

Note I'm calling MyMethod as a class member, not as a function (iter,first. You'll need to adjust your code to call your methods this way too, meaning you need to go through your list outside of the class instance.

The important bit to grasp is that you use . (or -> if you're accessing it through a pointer) to access your function member; you can't call it directly as a function.

The only other option you have is to add wrapper functions to your database.cc, defining the functions you're trying to call in your new main.cc.

Answer 2

Here is a new Database.cc that seems to compile.

It seems that the test main.cc calls free functions so I created new objects in every function stub.

And I added a constructor to Flightlist for list.

    // #include "stdafx.h" // uncomment for MS version
    #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);

    // --- CHANGES START ----------------

        Flightlist() {};
        ~Flightlist() {};
        Flightlist(list<Passenger> flistInput) : flist(flistInput){};
    private:
        list<Passenger> flist;
    };

    int menu() {
        static Flightlist FL; 
        return FL.menu();
    }

    void read_from_file(list<Passenger> flist, string s) {
        Flightlist FL(flist);
        FL.read_from_file(s);
    }

    void insert(list<Passenger> flist, string first, string last, string dest) {
        Flightlist FL(flist); 
        Passenger p(first, last, dest);
        FL.insert(p); 
    }

    void remove(list<Passenger> flist, string first, string last) {
        Flightlist FL(flist); 
        Passenger p(first, last, NULL);
        FL.remove(p);
    }

    bool check_reservation(list<Passenger> flist, string first, string last) {
        Flightlist FL(flist); 
        Passenger p(first, last, NULL);
        return FL.check_reservation(p);
    }

    void display_list(list<Passenger> flist) { 
        Flightlist FL(flist); 
        FL.display_list(); 
    }

    void save_to_file(list<Passenger> flist, string s) { 
        Flightlist FL(flist); 
        FL.save_to_file(s); 
    }

    // --- CHANGES STOP ----------------

    #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();
    }