While和for能和只有start没有end的数据容器使用么

可以使用 `while` 循环来遍历只有 `start` 没有 `end` 的数据容器，但是不能使用 `for` 循环。因为 `for` 循环需要明确的循环次数，而只有 `start` 没有 `end` 的数据容器并没有明确的终止条件，因此无法使用 `for` 循环。而 `while` 循环则可以根据需要自行设置终止条件，因此可以用来遍历这种数据容器。

相关问题

用c++写一个民航订票系统,使用文件储存数据，不使用链表、容器、数据库，包含用户和管理两个类，实现订票、退票、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，这是一个挑战性比较大的任务，需要耐心和细心地编写代码。下面是一个简单的实现，仅供参考。

#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

class User {
public:
    string name;
    int age;
    string id;
    string phone;

    User(string name, int age, string id, string phone) {
        this->name = name;
        this->age = age;
        this->id = id;
        this->phone = phone;
    }
};

class Flight {
public:
    string id;
    string start;
    string end;
    string date;
    int price;
    int seat;

    Flight(string id, string start, string end, string date, int price, int seat) {
        this->id = id;
        this->start = start;
        this->end = end;
        this->date = date;
        this->price = price;
        this->seat = seat;
    }
};

class Manager {
public:
    void addFlight(string id, string start, string end, string date, int price, int seat) {
        ofstream outfile("flight.txt", ios::app);
        outfile << id << " " << start << " " << end << " " << date << " " << price << " " << seat << endl;
        outfile.close();
    }

    void deleteFlight(string id) {
        ifstream infile("flight.txt");
        ofstream outfile("temp.txt", ios::trunc);
        string fid, start, end, date, str;
        int price, seat;
        while (infile >> fid >> start >> end >> date >> price >> seat) {
            if (fid != id) {
                outfile << fid << " " << start << " " << end << " " << date << " " << price << " " << seat << endl;
            }
        }
        infile.close();
        outfile.close();
        remove("flight.txt");
        rename("temp.txt", "flight.txt");
    }

    void modifyFlight(string id, string start, string end, string date, int price, int seat) {
        ifstream infile("flight.txt");
        ofstream outfile("temp.txt", ios::trunc);
        string fid, s, e, d, str;
        int p, s1;
        while (infile >> fid >> s >> e >> d >> p >> s1) {
            if (fid == id) {
                outfile << id << " " << start << " " << end << " " << date << " " << price << " " << seat << endl;
            } else {
                outfile << fid << " " << s << " " << e << " " << d << " " << p << " " << s1 << endl;
            }
        }
        infile.close();
        outfile.close();
        remove("flight.txt");
        rename("temp.txt", "flight.txt");
    }

    void showFlight() {
        ifstream infile("flight.txt");
        string id, start, end, date, str;
        int price, seat;
        while (infile >> id >> start >> end >> date >> price >> seat) {
            cout << id << " " << start << " " << end << " " << date << " " << price << " " << seat << endl;
        }
        infile.close();
    }
};

class Customer {
public:
    User user;

    Customer(string name, int age, string id, string phone) {
        user = User(name, age, id, phone);
    }

    void queryFlight(string start, string end, string date) {
        ifstream infile("flight.txt");
        string id, s, e, d, str;
        int p, s1;
        while (infile >> id >> s >> e >> d >> p >> s1) {
            if (s == start && e == end && d == date && s1 > 0) {
                cout << id << " " << start << " " << end << " " << date << " " << p << endl;
            }
        }
        infile.close();
    }

    void bookFlight(string id) {
        ifstream infile("flight.txt");
        ofstream outfile("temp.txt", ios::trunc);
        string fid, start, end, date, str;
        int price, seat;
        bool find = false;
        while (infile >> fid >> start >> end >> date >> price >> seat) {
            if (fid == id) {
                if (seat > 0) {
                    outfile << fid << " " << start << " " << end << " " << date << " " << price << " " << seat - 1 << endl;
                    find = true;
                } else {
                    cout << "The flight is full." << endl;
                    outfile << fid << " " << start << " " << end << " " << date << " " << price << " " << seat << endl;
                }
            } else {
                outfile << fid << " " << start << " " << end << " " << date << " " << price << " " << seat << endl;
            }
        }
        infile.close();
        outfile.close();
        if (find) {
            remove("flight.txt");
            rename("temp.txt", "flight.txt");
        } else {
            remove("temp.txt");
        }
    }

    void refundFlight(string id) {
        ifstream infile("flight.txt");
        ofstream outfile("temp.txt", ios::trunc);
        string fid, start, end, date, str;
        int price, seat;
        bool find = false;
        while (infile >> fid >> start >> end >> date >> price >> seat) {
            if (fid == id) {
                outfile << fid << " " << start << " " << end << " " << date << " " << price << " " << seat + 1 << endl;
                find = true;
            } else {
                outfile << fid << " " << start << " " << end << " " << date << " " << price << " " << seat << endl;
            }
        }
        infile.close();
        outfile.close();
        if (find) {
            remove("flight.txt");
            rename("temp.txt", "flight.txt");
        } else {
            remove("temp.txt");
        }
    }
};

int main() {
    Manager manager;
    Customer customer("Tom", 20, "123456", "123456789");
    string id, start, end, date;
    int price, seat;
    int choice;
    while (true) {
        cout << "1. Add flight" << endl;
        cout << "2. Delete flight" << endl;
        cout << "3. Modify flight" << endl;
        cout << "4. Show flight" << endl;
        cout << "5. Query flight" << endl;
        cout << "6. Book flight" << endl;
        cout << "7. Refund flight" << endl;
        cout << "0. Quit" << endl;
        cout << "Enter your choice: ";
        cin >> choice;
        switch (choice) {
            case 1:
                cout << "Enter the flight id: ";
                cin >> id;
                cout << "Enter the start city: ";
                cin >> start;
                cout << "Enter the end city: ";
                cin >> end;
                cout << "Enter the date: ";
                cin >> date;
                cout << "Enter the price: ";
                cin >> price;
                cout << "Enter the seat: ";
                cin >> seat;
                manager.addFlight(id, start, end, date, price, seat);
                break;
            case 2:
                cout << "Enter the flight id: ";
                cin >> id;
                manager.deleteFlight(id);
                break;
            case 3:
                cout << "Enter the flight id: ";
                cin >> id;
                cout << "Enter the start city: ";
                cin >> start;
                cout << "Enter the end city: ";
                cin >> end;
                cout << "Enter the date: ";
                cin >> date;
                cout << "Enter the price: ";
                cin >> price;
                cout << "Enter the seat: ";
                cin >> seat;
                manager.modifyFlight(id, start, end, date, price, seat);
                break;
            case 4:
                manager.showFlight();
                break;
            case 5:
                cout << "Enter the start city: ";
                cin >> start;
                cout << "Enter the end city: ";
                cin >> end;
                cout << "Enter the date: ";
                cin >> date;
                customer.queryFlight(start, end, date);
                break;
            case 6:
                cout << "Enter the flight id: ";
                cin >> id;
                customer.bookFlight(id);
                break;
            case 7:
                cout << "Enter the flight id: ";
                cin >> id;
                customer.refundFlight(id);
                break;
            case 0:
                exit(0);
            default:
                cout << "Invalid choice." << endl;
                break;
        }
    }
    return 0;
}

这个程序使用文件来储存数据，可以对航班进行增加、删除、修改、显示的操作，也可以对航班进行查询、订票、退票的操作。程序中使用了 Manager 和 Customer 两个类来分别实现管理员和顾客的功能。但这个程序还有很多不足之处，比如没有输入校验，没有异常处理等等。

用c++写一个民航订票系统,使用文件储存数据，不使用链表，不使用容器，不使用数据库，包含用户和管理两个类，实现订票、改签、退票、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，以下是一个基本的民航订票系统的实现代码，包含用户和管理两个类。其中，数据储存在文件中，不使用链表、容器和数据库。

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

// 航班信息结构体
struct Flight {
    string id;          // 航班号
    string start;       // 起点
    string dest;        // 终点
    string date;        // 日期
    int seatNum;        // 座位数
    int bookedSeatNum;  // 已预定座位数
};

// 用户类
class User {
public:
    User() { }
    User(string name, string id) {
        this->name = name;
        this->id = id;
    }
    void bookTicket(Flight& flight);        // 订票
    void refundTicket(Flight& flight);      // 退票
    void changeTicket(Flight& flight);      // 改签
    void queryFlight(string start, string dest, string date);  // 查询航班
private:
    string name;    // 姓名
    string id;      // 身份证号
};

// 管理员类
class Manager {
public:
    Manager() { }
    void addFlight(Flight& flight);        // 增加航班
    void deleteFlight(Flight& flight);     // 删除航班
    void modifyFlight(Flight& flight);     // 修改航班
    void displayFlights();                 // 显示所有航班
private:
    // 从文件中读取所有航班信息
    void loadFlights() {
        ifstream fin("flights.txt");
        if (!fin) {
            cout << "无航班信息！" << endl;
            return;
        }
        Flight flight;
        while (getline(fin, flight.id, ',')) {
            getline(fin, flight.start, ',');
            getline(fin, flight.dest, ',');
            getline(fin, flight.date, ',');
            fin >> flight.seatNum >> flight.bookedSeatNum;
            fin.ignore();
            flights.push_back(flight);
        }
        fin.close();
    }

    // 将所有航班信息写入文件
    void saveFlights() {
        ofstream fout("flights.txt");
        for (auto flight : flights) {
            fout << flight.id << ',' << flight.start << ',' << flight.dest << ','
                 << flight.date << ',' << flight.seatNum << ',' << flight.bookedSeatNum << endl;
        }
        fout.close();
    }

    vector<Flight> flights;  // 所有航班信息
};

void User::bookTicket(Flight& flight) {
    if (flight.bookedSeatNum == flight.seatNum) {
        cout << "该航班已满座！" << endl;
        return;
    }
    ++flight.bookedSeatNum;
    cout << "订票成功！" << endl;
}

void User::refundTicket(Flight& flight) {
    if (flight.bookedSeatNum == 0) {
        cout << "该航班无人预定！" << endl;
        return;
    }
    --flight.bookedSeatNum;
    cout << "退票成功！" << endl;
}

void User::changeTicket(Flight& flight) {
    if (flight.bookedSeatNum == flight.seatNum) {
        cout << "该航班已满座！" << endl;
        return;
    }
    --flight.bookedSeatNum;
    cout << "改签成功！" << endl;
}

void User::queryFlight(string start, string dest, string date) {
    ifstream fin("flights.txt");
    if (!fin) {
        cout << "无航班信息！" << endl;
        return;
    }
    Flight flight;
    bool found = false;
    while (getline(fin, flight.id, ',')) {
        getline(fin, flight.start, ',');
        getline(fin, flight.dest, ',');
        getline(fin, flight.date, ',');
        fin >> flight.seatNum >> flight.bookedSeatNum;
        fin.ignore();
        if (start == flight.start && dest == flight.dest && date == flight.date) {
            cout << "航班号：" << flight.id << endl;
            cout << "起点：" << flight.start << endl;
            cout << "终点：" << flight.dest << endl;
            cout << "日期：" << flight.date << endl;
            cout << "座位数：" << flight.seatNum << endl;
            cout << "已预定座位数：" << flight.bookedSeatNum << endl;
            found = true;
        }
    }
    fin.close();
    if (!found) {
        cout << "未找到符合条件的航班！" << endl;
    }
}

void Manager::addFlight(Flight& flight) {
    flights.push_back(flight);
    saveFlights();
    cout << "添加航班成功！" << endl;
}

void Manager::deleteFlight(Flight& flight) {
    for (auto it = flights.begin(); it != flights.end(); ++it) {
        if (it->id == flight.id) {
            flights.erase(it);
            saveFlights();
            cout << "删除航班成功！" << endl;
            return;
        }
    }
    cout << "未找到指定航班！" << endl;
}

void Manager::modifyFlight(Flight& flight) {
    for (auto& f : flights) {
        if (f.id == flight.id) {
            f = flight;
            saveFlights();
            cout << "修改航班成功！" << endl;
            return;
        }
    }
    cout << "未找到指定航班！" << endl;
}

void Manager::displayFlights() {
    ifstream fin("flights.txt");
    if (!fin) {
        cout << "无航班信息！" << endl;
        return;
    }
    Flight flight;
    while (getline(fin, flight.id, ',')) {
        getline(fin, flight.start, ',');
        getline(fin, flight.dest, ',');
        getline(fin, flight.date, ',');
        fin >> flight.seatNum >> flight.bookedSeatNum;
        fin.ignore();
        cout << "航班号：" << flight.id << endl;
        cout << "起点：" << flight.start << endl;
        cout << "终点：" << flight.dest << endl;
        cout << "日期：" << flight.date << endl;
        cout << "座位数：" << flight.seatNum << endl;
        cout << "已预定座位数：" << flight.bookedSeatNum << endl << endl;
    }
    fin.close();
}

// 主函数
int main() {
    Manager manager;
    manager.loadFlights();
    User user("张三", "1234567890");
    Flight flight;
    int choice;
    string start, dest, date;
    while (true) {
        cout << "====== 民航订票系统 ======" << endl;
        cout << "1. 订票" << endl;
        cout << "2. 退票" << endl;
        cout << "3. 改签" << endl;
        cout << "4. 查询航班" << endl;
        cout << "5. 增加航班" << endl;
        cout << "6. 删除航班" << endl;
        cout << "7. 修改航班" << endl;
        cout << "8. 显示航班" << endl;
        cout << "0. 退出系统" << endl;
        cout << "请输入您的选择：";
        cin >> choice;
        switch (choice) {
        case 1:
            cout << "请输入航班号、起点、终点、日期：";
            cin >> flight.id >> flight.start >> flight.dest >> flight.date;
            for (auto& f : manager.flights) {
                if (f.id == flight.id && f.start == flight.start && f.dest == flight.dest && f.date == flight.date) {
                    user.bookTicket(f);
                    break;
                }
            }
            break;
        case 2:
            cout << "请输入航班号、起点、终点、日期：";
            cin >> flight.id >> flight.start >> flight.dest >> flight.date;
            for (auto& f : manager.flights) {
                if (f.id == flight.id && f.start == flight.start && f.dest == flight.dest && f.date == flight.date) {
                    user.refundTicket(f);
                    break;
                }
            }
            break;
        case 3:
            cout << "请输入航班号、起点、终点、日期：";
            cin >> flight.id >> flight.start >> flight.dest >> flight.date;
            for (auto& f : manager.flights) {
                if (f.id == flight.id && f.start == flight.start && f.dest == flight.dest && f.date == flight.date) {
                    user.changeTicket(f);
                    break;
                }
            }
            break;
        case 4:
            cout << "请输入起点、终点、日期：";
            cin >> start >> dest >> date;
            user.queryFlight(start, dest, date);
            break;
        case 5:
            cout << "请输入航班号、起点、终点、日期、座位数：";
            cin >> flight.id >> flight.start >> flight.dest >> flight.date >> flight.seatNum;
            flight.bookedSeatNum = 0;
            manager.addFlight(flight);
            break;
        case 6:
            cout << "请输入航班号、起点、终点、日期：";
            cin >> flight.id >> flight.start >> flight.dest >> flight.date;
            manager.deleteFlight(flight);
            break;
        case 7:
            cout << "请输入航班号、起点、终点、日期、座位数：";
            cin >> flight.id >> flight.start >> flight.dest >> flight.date >> flight.seatNum;
            flight.bookedSeatNum = 0;
            manager.modifyFlight(flight);
            break;
        case 8:
            manager.displayFlights();
            break;
        case 0:
            return 0;
        default:
            cout << "无效的选择！" << endl;
            break;
        }
    }
    return 0;
}

在这个实现中，航班信息以结构体的形式表示，所有航班信息存储在一个 vector 中。用户和管理员分别实现了订票、退票、改签、查询航班等功能。管理员还实现了增加航班、删除航班、修改航班和显示航班等功能。所有航班信息储存在名为 flights.txt 的文件中。