c# 设计一个图书管理系统

设计一个简单的图书管理系统，包括以下类：

1、Book 类：表示一本图书，包括图书编号、书名、作者、出版日期等属性。

2、Library 类：表示图书馆，包括一个图书列表，可以添加图书、借出图书、归还图书等操作。

3、Person 类：表示图书馆的读者，包括姓名、借阅的图书列表等属性。

请用 C# 编写上述类，并提供简单的演示代码。

解答：

using System;
using System.Collections.Generic;

class Book
{
    public int BookId { get; set; }
    public string Title { get; set; }
    public string Author { get; set; }
    public DateTime PublicationDate { get; set; }
}

class Library
{
    private List<Book> books = new List<Book>();

    public void AddBook(Book book)
    {
        books.Add(book);
        Console.WriteLine($"Book '{book.Title}' added to the library.");
    }

    public void BorrowBook(Book book, Person person)
    {
        if (books.Contains(book))
        {
            books.Remove(book);
            person.BorrowedBooks.Add(book);
            Console.WriteLine($"{person.Name} borrowed the book '{book.Title}'.");
        }
        else
        {
            Console.WriteLine($"Sorry, the book '{book.Title}' is not available in the library.");
        }
    }

    public void ReturnBook(Book book, Person person)
    {
        if (person.BorrowedBooks.Contains(book))
        {
            person.BorrowedBooks.Remove(book);
            books.Add(book);
            Console.WriteLine($"{person.Name} returned the book '{book.Title}'.");
        }
        else
        {
            Console.WriteLine($"{person.Name} did not borrow the book '{book.Title}'.");
        }
    }
}

class Person
{
    public string Name { get; set; }
    public List<Book> BorrowedBooks { get; set; } = new List<Book>();
}

class Program
{
    static void Main()
    {
        Book book1 = new Book { BookId = 1, Title = "Introduction to C#", Author = "John Smith", PublicationDate = new DateTime(2020, 1, 1) };
        Book book2 = new Book { BookId = 2, Title = "Data Structures and Algorithms", Author = "Alice Johnson", PublicationDate = new DateTime(2019, 5, 15) };

        Library library = new Library();
        library.AddBook(book1);
        library.AddBook(book2);

        Person person1 = new Person { Name = "Alice" };
        Person person2 = new Person { Name = "Bob" };

        library.BorrowBook(book1, person1);
        library.BorrowBook(book2, person2);

        library.ReturnBook(book1, person1);
        library.ReturnBook(book2, person2);
    }
}