import java.awt.*;
import java.awt.event.*;
import java.util.*;

class Labor42 extends Frame{
  class Student{
    public String name;
    public String grade;
    Student(String name, String grade){
      this.name = name;
      this.grade = grade;   }  }

  Button next, prev;
  Panel studentPanel;
  TextField studentName;
  TextField studentGrade;

  int studentNumber = 0;
  ArrayList<Student> studentList;

  void displayStudent(){
    Student tmpStudent = studentList.get(studentNumber);
    studentName.setText(tmpStudent.name);
    studentGrade.setText(tmpStudent.grade);  }

  void nextStudent(){
    studentNumber = studentNumber<studentList.size()-1 ? studentNumber+1 : 0;
    displayStudent();  }

  void prevStudent(){
    studentNumber = studentNumber>0 ? studentNumber-1 : studentList.size()-1;
    displayStudent();  }

  Labor42(){
    studentList = new ArrayList<Student>();
    studentList.add(new Student("Aladar", "5"));
    studentList.add(new Student("Bela", "3"));
    studentList.add(new Student("Cecil", "4"));

    addWindowListener(new WindowAdapter() {
                  public void windowClosing(WindowEvent e) {
                        e.getWindow().dispose();                  }            });

    next= new Button(">");
    prev= new Button("<");
    prev.addActionListener( new ActionListener(){
        public void actionPerformed(ActionEvent e){
            prevStudent();        }    });

    next.addActionListener( new ActionListener(){
        public void actionPerformed(ActionEvent e){
            nextStudent();        }    });

    studentName= new TextField();
    studentGrade= new TextField();
    studentPanel = new Panel();
    studentPanel.setLayout(new GridLayout(2,1));
    studentPanel.add(studentName);
    studentPanel.add(studentGrade);
    add(prev, BorderLayout.WEST);
    add(next, BorderLayout.EAST);
    add(studentPanel, BorderLayout.CENTER);

    setSize(400, 200);

    setVisible(true);
  }

  public static void main(String[] args){
    new Labor42();
  }
}