运用c++，使用class类，写出一个书店管理系统的代码，要求完成以下功能:进货入库记录，销售出货记录，图书信息查询，自动预警提示，数据存储

好的，以下是一个基于C++的书店管理系统的代码示例，实现了进货入库记录、销售出货记录、图书信息查询、自动预警提示和数据存储等功能：

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

using namespace std;

// Book类，用于存储一本书的基本信息
class Book {
public:
    string name; // 书名
    string author; // 作者
    string publisher; // 出版社
    string ISBN; // ISBN号
    double price; // 售价
    double cost; // 进货价
    int stock; // 库存量
};

// Stock类，用于管理图书的库存信息
class Stock {
public:
    vector<Book> books; // 所有的图书信息
    vector<pair<string, int>> purchase_records; // 进货记录，每个元素是<进货时间, 进货数量>
    vector<pair<string, int>> sale_records; // 销售记录，每个元素是<销售时间, 销售数量>
    void add_book(Book book) { books.push_back(book); } // 添加图书
    void purchase(string time, int quantity) { purchase_records.push_back(make_pair(time, quantity)); } // 进货
    void sale(string time, int quantity) { sale_records.push_back(make_pair(time, quantity)); } // 销售
};

// Store类，用于管理整个书店的进货、销售、查询等操作
class Store {
public:
    Stock stock; // 库存信息
    double alert_threshold; // 库存预警阈值
    void add_book(Book book) { stock.add_book(book); } // 添加图书
    void purchase(string time, int quantity) { stock.purchase(time, quantity); } // 进货
    void sale(string time, int quantity) { stock.sale(time, quantity); } // 销售
    vector<Book> query(string keyword) { // 按关键字查询图书信息
        vector<Book> result;
        for (Book book : stock.books) {
            if (book.name.find(keyword) != string::npos || book.author.find(keyword) != string::npos || book.publisher.find(keyword) != string::npos) {
                result.push_back(book);
            }
        }
        return result;
    }
    void set_alert_threshold(double threshold) { alert_threshold = threshold; } // 设置库存预警阈值
    void alert() { // 库存预警提示
        for (Book book : stock.books) {
            if (book.stock < alert_threshold) {
                cout << "Warning: " << book.name << " stock is low (" << book.stock << ")" << endl;
            }
        }
    }
    void save() { // 将数据存储到文件中
        ofstream fout("data.txt");
        fout << alert_threshold << endl;
        fout << stock.purchase_records.size() << endl;
        for (auto record : stock.purchase_records) {
            fout << record.first << " " << record.second << endl;
        }
        fout << stock.sale_records.size() << endl;
        for (auto record : stock.sale_records) {
            fout << record.first << " " << record.second << endl;
        }
        fout << stock.books.size() << endl;
        for (Book book : stock.books) {
            fout << book.name << " " << book.author << " " << book.publisher << " " << book.ISBN << " " << book.price << " " << book.cost << " " << book.stock << endl;
        }
        fout.close();
    }
    void load() { // 从文件中读取数据
        ifstream fin("data.txt");
        fin >> alert_threshold;
        int n;
        fin >> n;
        for (int i = 0; i < n; i++) {
            string time;
            int quantity;
            fin >> time >> quantity;
            stock.purchase_records.push_back(make_pair(time, quantity));
        }
        fin >> n;
        for (int i = 0; i < n; i++) {
            string time;
            int quantity;
            fin >> time >> quantity;
            stock.sale_records.push_back(make_pair(time, quantity));
        }
        fin >> n;
        for (int i = 0; i < n; i++) {
            Book book;
            fin >> book.name >> book.author >> book.publisher >> book.ISBN >> book.price >> book.cost >> book.stock;
            stock.books.push_back(book);
        }
        fin.close();
    }
};

int main() {
    Store store;
    store.load(); // 从文件中读取数据

    while (true) {
        cout << "Please select an operation:" << endl;
        cout << "1. Add book" << endl;
        cout << "2. Purchase" << endl;
        cout << "3. Sale" << endl;
        cout << "4. Query" << endl;
        cout << "5. Set alert threshold" << endl;
        cout << "6. Alert" << endl;
        cout << "7. Save and quit" << endl;
        int op;
        cin >> op;
        switch (op) {
        case 1: {
            Book book;
            cout << "Please input book name: ";
            cin >> book.name;
            cout << "Please input author: ";
            cin >> book.author;
            cout << "Please input publisher: ";
            cin >> book.publisher;
            cout << "Please input ISBN: ";
            cin >> book.ISBN;
            cout << "Please input price: ";
            cin >> book.price;
            cout << "Please input cost: ";
            cin >> book.cost;
            cout << "Please input stock: ";
            cin >> book.stock;
            store.add_book(book);
            break;
        }
        case 2: {
            string time;
            int quantity;
            cout << "Please input purchase time (e.g. 2022-01-01): ";
            cin >> time;
            cout << "Please input purchase quantity: ";
            cin >> quantity;
            store.purchase(time, quantity);
            break;
        }
        case 3: {
            string time;
            int quantity;
            cout << "Please input sale time (e.g. 2022-01-01): ";
            cin >> time;
            cout << "Please input sale quantity: ";
            cin >> quantity;
            store.sale(time, quantity);
            break;
        }
        case 4: {
            cout << "Please input keyword: ";
            string keyword;
            cin >> keyword;
            vector<Book> result = store.query(keyword);
            for (Book book : result) {
                cout << book.name << " " << book.author << " " << book.publisher << " " << book.ISBN << " " << book.price << " " << book.cost << " " << book.stock << endl;
            }
            break;
        }
        case 5: {
            double threshold;
            cout << "Please input alert threshold: ";
            cin >> threshold;
            store.set_alert_threshold(threshold);
            break;
        }
        case 6: {
            store.alert();
            break;
        }
        case 7: {
            store.save(); // 将数据存储到文件中
            return 0;
        }
        default:
            cout << "Invalid operation!" << endl;
            break;
        }
    }

    return 0;
}

以上是一个简单的书店管理系统的代码示例，可以根据实际需求进行修改和完善。