/*
 * Shisoku.java --- 四則演算プログラム (GUI 版)
 */

import java.awt.*;       // Frame
import java.awt.event.*; // WindowAdapter 等

public class Shisoku extends Frame implements ActionListener {
  TextField tf_a, tf_b, wa, sa, seki, syou;
  Button bt, bt2;

  Shisoku() {
    setSize(400, 400);
    addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });

    setLayout(new GridLayout(7,2));
    add(new Label("a"));
    tf_a = new TextField("0", 10);
    add(tf_a);
    add(new Label("b"));
    tf_b = new TextField("0", 10);
    add(tf_b);
    add(new Label("a+b="));
    wa = new TextField("0", 10); add(wa);
    add(new Label("a-b="));
    sa = new TextField("0", 10); add(sa);
    add(new Label("a*b="));
    seki = new TextField("0", 10); add(seki);
    add(new Label("a/b="));
    syou = new TextField("0", 10); add(syou);
    bt = new Button("start");
    add(bt);
    bt.addActionListener(this); 
    bt2 = new Button("exit");
    add(bt2);
    bt2.addActionListener(this); 
  }

  public void actionPerformed(ActionEvent e) {
    if (e.getSource() == bt) {
      double a = Double.valueOf(tf_a.getText().trim()).doubleValue();
      double b = Double.valueOf(tf_b.getText().trim()).doubleValue();
      wa.setText("" + (a + b));
      sa.setText("" + (a - b));
      seki.setText("" + (a * b));
      syou.setText("" + (a / b));
    }
    else if (e.getSource() == bt2) {
      System.exit(0);
    }
  }

  public static void main(String args[]) {
    Frame f = new Shisoku();
    f.show();
  }
}