c++面向对象程序设计：设计一个小型的图书借阅管理系统，其中涉及到两个主体：学生和图书。学生需要借阅图书。图书对象都具有相同的属性：图书条形码、图书名称、图书被借次数、是否在架；并具有相同的操作：初始化属性值、修改属性值、显示属性值。对所有图书对象抽象成一个图书类。所有的学生具有相同的属性：学号、姓名、性别、借阅册数限制、在借册数；并具有相同的操作：初始化属性值、修改属性值、显示属性值。对所有学生对象抽象成一个学生类。 学生需要借阅图书，其涉及的属性有：读者编号（即学号）、图书条形码、借出时间、归还时间；其涉及的操作有：借书、还书。给出相应代码并用main函数进行测试。

好的，下面是一个示例的 C++ 代码实现，供你参考：

#include <iostream>
#include <string>
#include <vector>
#include <ctime>
using namespace std;

class Book {
private:
    string barcode; // 图书条形码
    string name; // 图书名称
    int borrowed_times; // 图书被借次数
    bool on_shelf; // 是否在架
public:
    // 构造函数
    Book(string barcode, string name, int borrowed_times = 0, bool on_shelf = true) {
        this->barcode = barcode;
        this->name = name;
        this->borrowed_times = borrowed_times;
        this->on_shelf = on_shelf;
    }

    // 显示属性值
    void display() {
        cout << "Barcode: " << barcode << endl;
        cout << "Name: " << name << endl;
        cout << "Borrowed times: " << borrowed_times << endl;
        cout << "On shelf: " << (on_shelf ? "Yes" : "No") << endl;
    }

    // 修改属性值
    void modify(string barcode = "", string name = "", int borrowed_times = -1, bool on_shelf = false) {
        if (!barcode.empty()) this->barcode = barcode;
        if (!name.empty()) this->name = name;
        if (borrowed_times != -1) this->borrowed_times = borrowed_times;
        if (on_shelf) this->on_shelf = on_shelf;
    }
};

class Student {
private:
    string student_id; // 学号
    string name; // 姓名
    string gender; // 性别
    int borrow_limit; // 借阅册数限制
    int borrowed_count; // 在借册数
public:
    // 构造函数
    Student(string student_id, string name, string gender, int borrow_limit = 5, int borrowed_count = 0) {
        this->student_id = student_id;
        this->name = name;
        this->gender = gender;
        this->borrow_limit = borrow_limit;
        this->borrowed_count = borrowed_count;
    }

    // 显示属性值
    void display() {
        cout << "Student ID: " << student_id << endl;
        cout << "Name: " << name << endl;
        cout << "Gender: " << gender << endl;
        cout << "Borrow limit: " << borrow_limit << endl;
        cout << "Borrowed count: " << borrowed_count << endl;
    }

    // 修改属性值
    void modify(string student_id = "", string name = "", string gender = "", int borrow_limit = -1, int borrowed_count = -1) {
        if (!student_id.empty()) this->student_id = student_id;
        if (!name.empty()) this->name = name;
        if (!gender.empty()) this->gender = gender;
        if (borrow_limit != -1) this->borrow_limit = borrow_limit;
        if (borrowed_count != -1) this->borrowed_count = borrowed_count;
    }
};

class Borrow {
private:
    string student_id; // 学号
    string barcode; // 图书条形码
    time_t borrow_time; // 借出时间
    time_t return_time; // 归还时间
public:
    // 构造函数
    Borrow(string student_id, string barcode) {
        this->student_id = student_id;
        this->barcode = barcode;
        this->borrow_time = time(NULL);
        this->return_time = 0;
    }

    // 归还图书
    void return_book() {
        this->return_time = time(NULL);
    }

    // 显示借阅信息
    void display() {
        cout << "Student ID: " << student_id << endl;
        cout << "Barcode: " << barcode << endl;
        cout << "Borrow time: " << ctime(&borrow_time);
        cout << "Return time: " << (return_time ? ctime(&return_time) : "Not returned yet") << endl;
    }
};

int main() {
    // 初始化图书和学生
    Book book1("001", "The Great Gatsby", 5, true);
    Book book2("002", "To Kill a Mockingbird", 3, true);
    Student student1("001", "Alice", "Female", 5, 0);
    Student student2("002", "Bob", "Male", 3, 0);

    // 显示图书和学生信息
    cout << "Book 1:" << endl;
    book1.display();
    cout << endl;

    cout << "Book 2:" << endl;
    book2.display();
    cout << endl;

    cout << "Student 1:" << endl;
    student1.display();
    cout << endl;

    cout << "Student 2:" << endl;
    student2.display();
    cout << endl;

    // 学生借阅图书
    Borrow borrow1("001", "001");
    student1.modify("", "", "", 5, 1);
    book1.modify("", "", 6, false);

    Borrow borrow2("002", "002");
    student2.modify("", "", "", 3, 1);
    book2.modify("", "", 4, false);

    // 显示借阅信息
    cout << "Borrow 1:" << endl;
    borrow1.display();
    cout << endl;

    cout << "Borrow 2:" << endl;
    borrow2.display();
    cout << endl;

    // 学生归还图书
    borrow1.return_book();
    student1.modify("", "", "", 5, 0);
    book1.modify("", "", 7, true);

    borrow2.return_book();
    student2.modify("", "", "", 3, 0);
    book2.modify("", "", 5, true);

    // 显示更新后的图书和学生信息
    cout << "Book 1:" << endl;
    book1.display();
    cout << endl;

    cout << "Book 2:" << endl;
    book2.display();
    cout << endl;

    cout << "Student 1:" << endl;
    student1.display();
    cout << endl;

    cout << "Student 2:" << endl;
    student2.display();
    cout << endl;

    return 0;
}

在上面的代码中，我们定义了一个 `Book` 类、一个 `Student` 类和一个 `Borrow` 类，分别表示图书、学生和借阅信息。在 `Book` 类和 `Student` 类中，我们定义了相应的属性和操作，与之前的要求相同。在 `Borrow` 类中，我们定义了借阅信息的属性和操作，包括借出时间、归还时间等。在 `main` 函数中，我们初始化了两个图书和两个学生，并进行了借阅和归还操作。最后，我们显示了更新后的图书和学生信息。