用Python面向对象写出图书管理系统

下面是用面向对象思想写出图书管理系统的一种方法：

class Book:
    def __init__(self, title, author):
        self.title = title
        self.author = author
        self.borrowed = False
        
    def borrow(self):
        if not self.borrowed:
            self.borrowed = True
            print("借阅成功！")
        else:
            print("该书已经被借走！")
            
    def return_book(self):
        if self.borrowed:
            self.borrowed = False
            print("还书成功！")
        else:
            print("该书没有被借走！")

class Library:
    def __init__(self):
        self.books = []
        
    def add_book(self, book):
        self.books.append(book)
        print("成功添加图书：", book.title)
        
    def list_books(self):
        for book in self.books:
            print("书名：", book.title, "  作者：", book.author, "  状态：", "已借出" if book.borrowed else "未借出")
            
    def borrow_book(self, title):
        for book in self.books:
            if book.title == title:
                book.borrow()
                break
        else:
            print("该图书不存在！")
            
    def return_book(self, title):
        for book in self.books:
            if book.title == title:
                book.return_book()
                break
        else:
            print("该图书不存在！")

这里的图书管理系统可以实现的功能有：添加图书、列出图书列表、借阅图书、还书。