写一个图书馆管理系统代码

创建一个简单的图书管理系统，我们可以考虑用Python编写一个基础版本。这里将展示一个基本的命令行界面，包括添加书籍、查询书籍、借阅和归还书籍的功能。请注意，这只是一个简化版的示例，并未包含数据库连接等复杂功能。

class Book:
    def __init__(self, title, author, available):
        self.title = title
        self.author = author
        self.available = available

class Library:
    def __init__(self):
        self.books = []

    def add_book(self, book):
        self.books.append(book)

    def search_book(self, title):
        for book in self.books:
            if book.title == title:
                return book
        return None

    def borrow_book(self, title):
        book = self.search_book(title)
        if book and book.available:
            book.available = False
            print(f"Book '{title}' borrowed.")
        else:
            print("Book not found or already borrowed.")

    def return_book(self, title):
        book = self.search_book(title)
        if book and not book.available:
            book.available = True
            print(f"Book '{title}' returned.")
        else:
            print("Invalid action.")

# 创建图书馆实例
library = Library()

# 添加书籍
book1 = Book("Python Programming", "John Doe", True)
book2 = Book("Data Structures", "Jane Smith", True)
library.add_book(book1)
library.add_book(book2)

# 操作书籍
library.borrow_book("Python Programming")
library.return_book("Data Structures")