 class Student                                  //
    {
         public int stu_no;                          //ѧ
         public String stu_name;                     //ѧ
         public String specialty;                     //רҵ         
         static int stu_NextNo = 1001 ;                
         static int lengthOfSchool = 4;                //ѧ
         Student () {
             stu_no = stu_NextNo++;                     
         }
         static int getLengthOfSchool(){
               return lengthOfSchool;
         }
         int getStu_no (){
             return stu_no;                       
         }
         String getStu_name (){
             return stu_name;                       
         }
         void setStu_name (String name ) {
             stu_name = name;                       
         }
         String getSpecialty (){
             return specialty;                       
         }
         void setSpecialty (String spec ) {
             specialty = spec;                       
         }
         public String toString(){                  //ۺѧϢ
             String s;
             s = "ѧţ" + stu_no + "; " + stu_name + "; רҵ" + specialty;
             return s;
         }
    }//end Student
    public class GraduateStudent extends Student{
         public String tutor;                          //ʦ
         public String spec_direction;                  //о
         String getTutor () {
             return tutor;                       
         }
         void setTutor(String stu_tutor) {
             tutor = stu_tutor;                       
         }
         String getSpec_direction (){
             return spec_direction;                       
         }
         void setSpec_direction (String direction ) {
             spec_direction = direction;                       
         }
         public static void main(String[] args) {
           GraduateStudent stu1 = new GraduateStudent();                       
           stu1.setStu_name("");                 //ø෽
           stu1.setSpecialty ("Ӧü");         //ø෽
           stu1.setSpec_direction ("˹");          //෽
           stu1.setTutor ("");                    //෽
           System.out.println(stu1.toString()+";о"+stu1.spec_direction 
           + ";ʦ:" + stu1.tutor );           
         }
    }//end GraduateStudent
