1     class Book//类名用帕斯卡命名法
 2     {
 3         public string BookName, Author;//书名, 作者(字段)
 4         public int Price;//价格(字段)
 5         public Book()//无参构造函数
 6         {
 7             BookName = "C#";
 8             Author = "Sophie Wang";
 9             Price = 99;
10         }
11         public Book(string bookName2, string Author2, int Price2)//有参构造函数(参数用驼峰命名法)
12         {
13             BookName = bookName2;
14             Author = Author2;
15             Price = Price2;
16         }
17     }//两个构造函数中用的字段是一样的
18     class Program
19     {
20        
21         static void Main(string[] args)
22         {//对象是类的实例化
23             Book book1 = new Book();//创建Book类的一个对象book1
24             Console.WriteLine($"书名:{book1.BookName} ");
25             Console.WriteLine($"作者:{book1.Author} ");
26             Console.WriteLine($"价格:{book1.Price} ");
27             Console.WriteLine("--------------------------------------");
28             Book book2 = new Book("C++", "Chenfei Wang", 100);//创建Book类的第二个对象book2(有参构造函数需要从外部输入实参)
29             Console.WriteLine($"书名:{book2.BookName} ");
30             Console.WriteLine($"作者:{book2.Author} ");
31             Console.WriteLine($"价格:{book2.Price} ");
32             Console.ReadKey();
33             
34         }
35     }