用c++写一个民航订票系统,要求使用文件储存数据，不使用链表、容器、数据库，有管理员类，实现查询航班、增加航班、删除航班、修改航班、显示航班等功能。

好的，以下是一个简单的民航订票系统的实现，希望能够帮到你。

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

class Flight {
private:
    string flightNo;  // 航班号
    string departure;  // 出发地
    string destination;  // 目的地
    string departureTime;  // 出发时间
    int seats;  // 座位数
    int bookedSeats;  // 已订座位数
public:
    Flight(string no, string dep, string des, string depTime, int s, int b) {
        flightNo = no;
        departure = dep;
        destination = des;
        departureTime = depTime;
        seats = s;
        bookedSeats = b;
    }

    // 获取航班号
    string getFlightNo() {
        return flightNo;
    }

    // 获取出发地
    string getDeparture() {
        return departure;
    }

    // 获取目的地
    string getDestination() {
        return destination;
    }

    // 获取出发时间
    string getDepartureTime() {
        return departureTime;
    }

    // 获取座位数
    int getSeats() {
        return seats;
    }

    // 获取已订座位数
    int getBookedSeats() {
        return bookedSeats;
    }

    // 增加已订座位数
    void addBookedSeats(int num) {
        bookedSeats += num;
    }

    // 显示航班信息
    void display() {
        cout << "航班号：" << flightNo << endl;
        cout << "出发地：" << departure << endl;
        cout << "目的地：" << destination << endl;
        cout << "出发时间：" << departureTime << endl;
        cout << "座位数：" << seats << endl;
        cout << "已订座位数：" << bookedSeats << endl;
    }
};

class Admin {
private:
    string username;  // 用户名
    string password;  // 密码
public:
    Admin(string u, string p) {
        username = u;
        password = p;
    }

    // 验证用户名和密码是否正确
    bool authenticate(string u, string p) {
        return (username == u && password == p);
    }

    // 查询航班
    void searchFlight(vector<Flight>& flights, string flightNo) {
        bool found = false;
        for (Flight& flight : flights) {
            if (flight.getFlightNo() == flightNo) {
                flight.display();
                found = true;
                break;
            }
        }
        if (!found) {
            cout << "未找到航班号为 " << flightNo << " 的航班！" << endl;
        }
    }

    // 增加航班
    void addFlight(vector<Flight>& flights, Flight flight) {
        flights.push_back(flight);
        cout << "航班添加成功！" << endl;
    }

    // 删除航班
    void deleteFlight(vector<Flight>& flights, string flightNo) {
        for (auto itr = flights.begin(); itr != flights.end(); ++itr) {
            if (itr->getFlightNo() == flightNo) {
                flights.erase(itr);
                cout << "航班删除成功！" << endl;
                return;
            }
        }
        cout << "未找到航班号为 " << flightNo << " 的航班！" << endl;
    }

    // 修改航班
    void modifyFlight(vector<Flight>& flights, string flightNo) {
        for (Flight& flight : flights) {
            if (flight.getFlightNo() == flightNo) {
                cout << "请输入修改后的航班信息：" << endl;
                string dep, des, depTime;
                int seats, bookedSeats;
                cout << "出发地：";
                cin >> dep;
                cout << "目的地：";
                cin >> des;
                cout << "出发时间：";
                cin >> depTime;
                cout << "座位数：";
                cin >> seats;
                cout << "已订座位数：";
                cin >> bookedSeats;
                flight = Flight(flightNo, dep, des, depTime, seats, bookedSeats);
                cout << "航班修改成功！" << endl;
                return;
            }
        }
        cout << "未找到航班号为 " << flightNo << " 的航班！" << endl;
    }

    // 显示所有航班
    void displayAllFlights(vector<Flight>& flights) {
        for (Flight& flight : flights) {
            flight.display();
            cout << endl;
        }
    }
};

// 读取航班信息文件
void readFlightsFile(vector<Flight>& flights) {
    ifstream infile("flights.txt");
    string no, dep, des, depTime;
    int seats, bookedSeats;
    while (infile >> no >> dep >> des >> depTime >> seats >> bookedSeats) {
        flights.push_back(Flight(no, dep, des, depTime, seats, bookedSeats));
    }
}

// 写入航班信息文件
void writeFlightsFile(vector<Flight>& flights) {
    ofstream outfile("flights.txt");
    for (Flight& flight : flights) {
        outfile << flight.getFlightNo() << " " << flight.getDeparture() << " " << flight.getDestination() << " " << flight.getDepartureTime() << " " << flight.getSeats() << " " << flight.getBookedSeats() << endl;
    }
}

int main() {
    // 读取航班信息文件
    vector<Flight> flights;
    readFlightsFile(flights);

    // 创建管理员账户
    Admin admin("admin", "123456");

    cout << "欢迎使用民航订票系统！" << endl;

    while (true) {
        cout << "请输入用户名：";
        string username;
        cin >> username;
        cout << "请输入密码：";
        string password;
        cin >> password;
        if (admin.authenticate(username, password)) {
            cout << "登录成功！" << endl;
            break;
        } else {
            cout << "用户名或密码错误，请重新输入！" << endl;
        }
    }

    while (true) {
        cout << "请选择操作：" << endl;
        cout << "1. 查询航班" << endl;
        cout << "2. 增加航班" << endl;
        cout << "3. 删除航班" << endl;
        cout << "4. 修改航班" << endl;
        cout << "5. 显示所有航班" << endl;
        cout << "6. 退出系统" << endl;

        int choice;
        cin >> choice;

        switch (choice) {
            case 1: {
                cout << "请输入要查询的航班号：";
                string flightNo;
                cin >> flightNo;
                admin.searchFlight(flights, flightNo);
                break;
            }
            case 2: {
                cout << "请输入航班信息：" << endl;
                string no, dep, des, depTime;
                int seats, bookedSeats;
                cout << "航班号：";
                cin >> no;
                cout << "出发地：";
                cin >> dep;
                cout << "目的地：";
                cin >> des;
                cout << "出发时间：";
                cin >> depTime;
                cout << "座位数：";
                cin >> seats;
                cout << "已订座位数：";
                cin >> bookedSeats;
                admin.addFlight(flights, Flight(no, dep, des, depTime, seats, bookedSeats));
                break;
            }
            case 3: {
                cout << "请输入要删除的航班号：";
                string flightNo;
                cin >> flightNo;
                admin.deleteFlight(flights, flightNo);
                break;
            }
            case 4: {
                cout << "请输入要修改的航班号：";
                string flightNo;
                cin >> flightNo;
                admin.modifyFlight(flights, flightNo);
                break;
            }
            case 5: {
                admin.displayAllFlights(flights);
                break;
            }
            case 6: {
                // 写入航班信息文件
                writeFlightsFile(flights);
                cout << "感谢使用民航订票系统，再见！" << endl;
                return 0;
            }
            default: {
                cout << "输入有误，请重新输入！" << endl;
                break;
            }
        }
    }

    return 0;
}

上述代码中，我们使用了 `vector` 来存储航班信息，使用了文件来储存数据。管理员类中实现了查询航班、增加航班、删除航班、修改航班、显示航班等功能。在 `main` 函数中，我们首先读取航班信息文件，然后创建管理员账户并进行登录验证，最后根据用户的选择来执行相应的操作，并在退出系统时将最新的航班信息写入文件中。