用c++类和文件写火车购票管理系统的代码

下面是一个简单的火车购票管理系统的代码，使用了C++类和文件来实现：

#include <iostream>
#include <fstream> // 文件操作
#include <string>
using namespace std;

class Train {
private:
    string name;
    int numSeats;
public:
    Train() {}
    Train(string n, int s) : name(n), numSeats(s) {}

    string getName() const {
        return name;
    }

    int getNumSeats() const {
        return numSeats;
    }

    void reserveSeat() {
        if (numSeats > 0) {
            numSeats--;
            cout << "Successfully reserved a seat.\n";
        }
        else {
            cout << "Sorry, no more seats available.\n";
        }
    }

    void printInfo() const {
        cout << "Train name: " << name << '\n';
        cout << "Number of available seats: " << numSeats << '\n';
    }
};

class TrainManager {
private:
    Train trains[10];
    int numTrains;
public:
    TrainManager() : numTrains(0) {}

    void addTrain(const Train& t) {
        if (numTrains < 10) {
            trains[numTrains] = t;
            numTrains++;
            cout << "Successfully added a train.\n";
        }
        else {
            cout << "Sorry, the maximum number of trains has been reached.\n";
        }
    }

    void reserveSeat(const string& trainName) {
        for (int i = 0; i < numTrains; i++) {
            if (trains[i].getName() == trainName) {
                trains[i].reserveSeat();
                return;
            }
        }
        cout << "Train not found.\n";
    }

    void printTrainInfo(const string& trainName) const {
        for (int i = 0; i < numTrains; i++) {
            if (trains[i].getName() == trainName) {
                trains[i].printInfo();
                return;
            }
        }
        cout << "Train not found.\n";
    }

    void saveToFile(const string& fileName) const {
        ofstream outFile(fileName);
        if (outFile) {
            outFile << numTrains << '\n';
            for (int i = 0; i < numTrains; i++) {
                outFile << trains[i].getName() << '\n';
                outFile << trains[i].getNumSeats() << '\n';
            }
            cout << "Successfully saved data to file.\n";
        }
        else {
            cout << "Error: could not open file for writing.\n";
        }
    }

    void loadFromFile(const string& fileName) {
        ifstream inFile(fileName);
        if (inFile) {
            inFile >> numTrains;
            for (int i = 0; i < numTrains; i++) {
                string name;
                int numSeats;
                inFile >> name >> numSeats;
                trains[i] = Train(name, numSeats);
            }
            cout << "Successfully loaded data from file.\n";
        }
        else {
            cout << "Error: could not open file for reading.\n";
        }
    }
};

int main() {
    TrainManager manager;
    int choice;
    string trainName;
    string fileName;

    while (true) {
        cout << "1. Add train\n";
        cout << "2. Reserve seat\n";
        cout << "3. Print train info\n";
        cout << "4. Save to file\n";
        cout << "5. Load from file\n";
        cout << "6. Quit\n";
        cout << "Enter your choice: ";
        cin >> choice;

        switch (choice) {
        case 1:
            string name;
            int numSeats;
            cout << "Enter train name: ";
            cin >> name;
            cout << "Enter number of seats: ";
            cin >> numSeats;
            manager.addTrain(Train(name, numSeats));
            break;
        case 2:
            cout << "Enter train name: ";
            cin >> trainName;
            manager.reserveSeat(trainName);
            break;
        case 3:
            cout << "Enter train name: ";
            cin >> trainName;
            manager.printTrainInfo(trainName);
            break;
        case 4:
            cout << "Enter file name: ";
            cin >> fileName;
            manager.saveToFile(fileName);
            break;
        case 5:
            cout << "Enter file name: ";
            cin >> fileName;
            manager.loadFromFile(fileName);
            break;
        case 6:
            return 0;
        default:
            cout << "Invalid choice. Please try again.\n";
        }
    }

    return 0;
}

该程序使用Train类来表示每个火车，TrainManager类用于管理所有火车。用户可以添加新的火车，预订座位，打印火车信息，保存和加载数据到文件中。

在该程序中，我们使用了fstream库中的ofstream和ifstream类来进行文件的写入和读取。当用户选择保存数据时，程序将把当前所有火车的信息写入到指定的文件中；当用户选择从文件加载数据时，程序将从指定的文件中读取数据并恢复火车列表。