编写一个程序模拟图书管理系统。用户分为管理员和读者两类，分别显示不同文本格式菜单，通过菜单项对应数字进行选择。读者菜单包括借书、还书、查询等功能。管理员菜单包括图书和读者信息录入、修改和删除。图书信息至少应包括：编号、书名、数量，读者信息至少应包括：编号、姓名、所借图书。可根据图书名称或编号进行图书信息查询，可查询某本书现在被哪些读者借走。c++

好的，以下是一个简单的图书管理系统的C++代码：

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

using namespace std;

// 书籍结构体
struct Book {
    string id; // 编号
    string name; // 书名
    int quantity; // 数量
};

// 读者结构体
struct Reader {
    string id; // 编号
    string name; // 姓名
    vector<string> borrowed_books; // 所借图书编号
};

// 全局变量
vector<Book> books;
vector<Reader> readers;
int book_id_count = 0;
int reader_id_count = 0;

// 函数声明
void show_reader_menu();
void show_admin_menu();
void borrow_book();
void return_book();
void search_book();
void add_book();
void edit_book();
void delete_book();
void add_reader();
void edit_reader();
void delete_reader();
void search_borrowers();

// 主函数
int main() {
    // 初始化图书和读者
    books.push_back({"B001", "C++ Primer", 5});
    books.push_back({"B002", "Effective C++", 3});
    readers.push_back({"R001", "张三", {"B001", "B002"}});
    readers.push_back({"R002", "李四", {"B001"}});
    reader_id_count = 2;

    // 显示菜单
    cout << "欢迎使用图书管理系统" << endl;
    while (true) {
        cout << endl << "请选择用户类型：" << endl;
        cout << "1. 读者" << endl;
        cout << "2. 管理员" << endl;
        cout << "3. 退出" << endl;
        int user_type;
        cin >> user_type;
        switch (user_type) {
            case 1:
                show_reader_menu();
                break;
            case 2:
                show_admin_menu();
                break;
            case 3:
                cout << "再见！" << endl;
                return 0;
            default:
                cout << "无效的选项！" << endl;
        }
    }
}

// 显示读者菜单
void show_reader_menu() {
    while (true) {
        cout << endl << "请选择操作：" << endl;
        cout << "1. 借书" << endl;
        cout << "2. 还书" << endl;
        cout << "3. 查询图书" << endl;
        cout << "4. 查询借阅者" << endl;
        cout << "5. 返回" << endl;
        int choice;
        cin >> choice;
        switch (choice) {
            case 1:
                borrow_book();
                break;
            case 2:
                return_book();
                break;
            case 3:
                search_book();
                break;
            case 4:
                search_borrowers();
                break;
            case 5:
                return;
            default:
                cout << "无效的选项！" << endl;
        }
    }
}

// 显示管理员菜单
void show_admin_menu() {
    while (true) {
        cout << endl << "请选择操作：" << endl;
        cout << "1. 添加图书" << endl;
        cout << "2. 修改图书" << endl;
        cout << "3. 删除图书" << endl;
        cout << "4. 添加读者" << endl;
        cout << "5. 修改读者" << endl;
        cout << "6. 删除读者" << endl;
        cout << "7. 返回" << endl;
        int choice;
        cin >> choice;
        switch (choice) {
            case 1:
                add_book();
                break;
            case 2:
                edit_book();
                break;
            case 3:
                delete_book();
                break;
            case 4:
                add_reader();
                break;
            case 5:
                edit_reader();
                break;
            case 6:
                delete_reader();
                break;
            case 7:
                return;
            default:
                cout << "无效的选项！" << endl;
        }
    }
}

// 借书
void borrow_book() {
    cout << "请输入图书编号：" << endl;
    string book_id;
    cin >> book_id;
    for (Book& book : books) {
        if (book.id == book_id) {
            if (book.quantity > 0) {
                cout << "借书成功！" << endl;
                book.quantity--;
                for (Reader& reader : readers) {
                    if (reader.id == "R001") {
                        reader.borrowed_books.push_back(book_id);
                        return;
                    }
                }
            } else {
                cout << "该图书已全部借出，请稍后再试。" << endl;
            }
            return;
        }
    }
    cout << "输入的图书编号不存在！" << endl;
}

// 还书
void return_book() {
    cout << "请输入图书编号：" << endl;
    string book_id;
    cin >> book_id;
    for (Book& book : books) {
        if (book.id == book_id) {
            cout << "还书成功！" << endl;
            book.quantity++;
            for (Reader& reader : readers) {
                if (reader.id == "R001") {
                    for (int i = 0; i < reader.borrowed_books.size(); i++) {
                        if (reader.borrowed_books[i] == book_id) {
                            reader.borrowed_books.erase(reader.borrowed_books.begin() + i);
                            return;
                        }
                    }
                }
            }
            return;
        }
    }
    cout << "输入的图书编号不存在！" << endl;
}

// 查询图书
void search_book() {
    cout << "请选择查询方式：" << endl;
    cout << "1. 按编号查询" << endl;
    cout << "2. 按书名查询" << endl;
    int choice;
    cin >> choice;
    if (choice == 1) {
        cout << "请输入图书编号：" << endl;
        string book_id;
        cin >> book_id;
        for (const Book& book : books) {
            if (book.id == book_id) {
                cout << "编号：" << book.id << "，书名：" << book.name << "，数量：" << book.quantity << endl;
                return;
            }
        }
        cout << "输入的图书编号不存在！" << endl;
    } else if (choice == 2) {
        cout << "请输入书名关键字：" << endl;
        string keyword;
        cin >> keyword;
        bool found = false;
        for (const Book& book : books) {
            if (book.name.find(keyword) != string::npos) {
                found = true;
                cout << "编号：" << book.id << "，书名：" << book.name << "，数量：" << book.quantity << endl;
            }
        }
        if (!found) {
            cout << "未找到相关图书！" << endl;
        }
    } else {
        cout << "无效的选项！" << endl;
    }
}

// 添加图书
void add_book() {
    string id, name;
    int quantity;
    cout << "请输入图书编号：" << endl;
    cin >> id;
    cout << "请输入图书名称：" << endl;
    cin >> name;
    cout << "请输入图书数量：" << endl;
    cin >> quantity;
    books.push_back({id, name, quantity});
    cout << "添加成功！" << endl;
}

// 修改图书
void edit_book() {
    cout << "请输入要修改的图书编号：" << endl;
    string book_id;
    cin >> book_id;
    for (Book& book : books) {
        if (book.id == book_id) {
            cout << "请输入新的图书名称（留空表示不修改）：" << endl;
            string new_name;
            cin >> new_name;
            if (!new_name.empty()) {
                book.name = new_name;
            }
            cout << "请输入新的图书数量（留空表示不修改）：" << endl;
            int new_quantity;
            cin >> new_quantity;
            if (new_quantity > 0) {
                book.quantity = new_quantity;
            }
            cout << "修改成功！" << endl;
            return;
        }
    }
    cout << "输入的图书编号不存在！" << endl;
}

// 删除图书
void delete_book() {
    cout << "请输入要删除的图书编号：" << endl;
    string book_id;
    cin >> book_id;
    for (int i = 0; i < books.size(); i++) {
        if (books[i].id == book_id) {
            books.erase(books.begin() + i);
            cout << "删除成功！" << endl;
            return;
        }
    }
    cout << "输入的图书编号不存在！" << endl;
}

// 添加读者
void add_reader() {
    string name;
    cout << "请输入读者姓名：" << endl;
    cin >> name;
    readers.push_back({to_string(++reader_id_count), name, {}});
    cout << "添加成功！" << endl;
}

// 修改读者
void edit_reader() {
    cout << "请输入要修改的读者编号：" << endl;
    string reader_id;
    cin >> reader_id;
    for (Reader& reader : readers) {
        if (reader.id == reader_id) {
            cout << "请输入新的读者姓名（留空表示不修改）：" << endl;
            string new_name;
            cin >> new_name;
            if (!new_name.empty()) {
                reader.name = new_name;
            }
            cout << "修改成功！" << endl;
            return;
        }
    }
    cout << "输入的读者编号不存在！" << endl;
}

// 删除读者
void delete_reader() {
    cout << "请输入要删除的读者编号：" << endl;
    string reader_id;
    cin >> reader_id;
    for (int i = 0; i < readers.size(); i++) {
        if (readers[i].id == reader_id) {
            readers.erase(readers.begin() + i);
            cout << "删除成功！" << endl;
            return;
        }
    }
    cout << "输入的读者编号不存在！" << endl;
}

// 查询借阅者
void search_borrowers() {
    cout << "请输入图书编号：" << endl;
    string book_id;
    cin >> book_id;
    for (const Reader& reader : readers) {
        for (const string& borrowed_book_id : reader.borrowed_books) {
            if (borrowed_book_id == book_id) {
                cout << "读者编号：" << reader.id << "，姓名：" << reader.name << endl;
                break;
            }
        }
    }
}

以上代码实现了以下功能：

- 读者菜单：借书、还书、查询图书、查询借阅者
- 管理员菜单：添加图书、修改图书、删除图书、添加读者、修改读者、删除读者
- 可根据图书名称或编号进行图书信息查询
- 可查询某本书现在被哪些读者借走

注意，以上代码仅供参考，实际应用时还需要根据具体需求进行修改。