케찹만땅

import java.awt.GridLayout ;
import java.awt.BorderLayout ;

import javax.swing.JFrame ;
import javax.swing.JPanel ;
import javax.swing.JLabel ;
import javax.swing.JTextField ;
import javax.swing.JButton ;

import java.awt.event.ActionEvent ;
import java.awt.event.ActionListener ;

public class Fah2CelSwing extends JFrame implements ActionListener {
 JPanel panel = new JPanel() ;

 private JLabel labelFah ;
 private JLabel labelCel ;
 private JTextField textFieldFah ;
 private JTextField textFieldCel ;
 private JButton btn ; 

 Fah2CelSwing() {
  super() ;

  labelFah = new JLabel("화씨 온도") ;
  labelCel = new JLabel("섭씨 온도") ;

  textFieldFah = new JTextField() ;
  textFieldCel = new JTextField() ;

  btn = new JButton("화씨를 섭씨로 변환한다, 실시~잉.") ;

  panel.setLayout(new GridLayout(2, 2, 4, 4)) ;

  panel.add(labelFah) ;
  panel.add(textFieldFah) ;
  panel.add(labelCel) ;
  panel.add(textFieldCel) ; 

  textFieldFah.setHorizontalAlignment(JTextField.RIGHT) ;
  textFieldCel.setHorizontalAlignment(JTextField.RIGHT) ;
  
  this.add(panel, BorderLayout.CENTER) ; 
  this.add(btn, BorderLayout.SOUTH) ;
  btn.addActionListener(this) ;
 
  this.setTitle("화씨온도 ---> 섭씨온도 변환 버튼 액션 테스트") ;
  this.setSize(300, 120) ;
  this.setLocation(200, 200) ;
  this.setVisible(true) ;
  this.setDefaultCloseOperation(EXIT_ON_CLOSE) ;
 }
 public static void main(String[] args)  {
  Fah2CelSwing f2cS = new Fah2CelSwing() ;
 }
 public void actionPerformed(ActionEvent ae) {
  double fah = 5.0 / 9.0 * (Double.parseDouble( textFieldFah.getText() ) - 32) ;
  textFieldCel.setText(Double.toString(fah)) ;
 }
}