用代码生成一个图书馆管理系统

好的，以下是一个简单的图书馆管理系统的 Python 代码示例：

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

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

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

    def remove_book(self, book):
        self.books.remove(book)

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

    def checkout_book(self, title):
        book = self.search_book(title)
        if book is not None and book.copies > 0:
            book.copies -= 1
            return True
        return False

    def checkin_book(self, title):
        book = self.search_book(title)
        if book is not None:
            book.copies += 1
            return True
        return False

library = Library()
book1 = Book("Harry Potter and the Philosopher's Stone", "J.K. Rowling", "9780747532743", 5)
book2 = Book("The Lord of the Rings", "J.R.R. Tolkien", "9780544003415", 3)
library.add_book(book1)
library.add_book(book2)

while True:
    print("1. Search for a book")
    print("2. Checkout a book")
    print("3. Checkin a book")
    print("4. Exit")
    choice = input("Enter your choice: ")

    if choice == "1":
        title = input("Enter the title of the book: ")
        book = library.search_book(title)
        if book is not None:
            print("Title:", book.title)
            print("Author:", book.author)
            print("ISBN:", book.ISBN)
            print("Copies available:", book.copies)
        else:
            print("Book not found")

    elif choice == "2":
        title = input("Enter the title of the book: ")
        if library.checkout_book(title):
            print("Book checked out successfully")
        else:
            print("Book not available")

    elif choice == "3":
        title = input("Enter the title of the book: ")
        if library.checkin_book(title):
            print("Book checked in successfully")
        else:
            print("Book not found")

    elif choice == "4":
        break

    else:
        print("Invalid choice")

这个系统包括两个类：`Book` 类表示一本书，包括标题、作者、ISBN 号和副本数等属性；`Library` 类表示图书馆，包括一个可以添加、删除、搜索、借阅和归还书籍的方法。在 `Library` 类的构造函数中，我们初始化一个空的书籍列表。在 `while` 循环中，我们提供了四个选项：搜索书籍、借阅书籍、归还书籍和退出系统。用户可以根据需要选择适当的选项。