class Student                                      
      {
           public int stu_no;                               //ѧ
           public String stu_name;                          //ѧ
           public String specialty;                           //רҵ                  
           Student ()                        
           {
               System.out.print("create a student");                     
           }
           Student(String name)                        
           {
               this();                     //õǰһ췽
               System.out.print ("" + name);                     
           }
      }//end Student
      public class GraduateStudent extends Student
      {
           public String tutor;                        //ʦ
           public String spec_direction;                //о
           GraduateStudent (String name)                        
           {
               super(name);                   //øĹ췽
               System.out.println(",  he is a graduateStudent");                     
           }
           GraduateStudent (String name , String tutor , String spec)                        
           {
              this(name);                     //õǰһ췽
              System.out.println ("his tutor" + tutor 
                                + ", his specialty direction" + spec);                     
           }
           public static void main(String[] args)         
           {
              GraduateStudent stu1 = new GraduateStudent("John");                     
          GraduateStudent stu2 = new GraduateStudent("Tom", "Bill", "computer");
           }
      }//end GraduateStudent
