private static void Main(string[] args)
{
Student s3 = new Student("王五", null);
Student s1 = new Student("张三", s3);
Student s2 = new Student("李四", s1);
Book b1 = new Book("赵六");
s2.CheckBook(b1);
Console.ReadLine();
}
public Student(string name, Student nextStudent)
{
_name = name;
_nextStudent = nextStudent;
}