import java.lang.*;
import java.awt.*;
import java.awt.event.*;

public class thing
{ public static void main(String[] args)
  { new thing(); }
  
  private class window_watcher implements WindowListener
  { public void windowOpened(WindowEvent e) {}
    public void windowIconified(WindowEvent e) {}
    public void windowDeiconified(WindowEvent e) {}
    public void windowActivated(WindowEvent e) {}
    public void windowDeactivated(WindowEvent e) {}
    public void windowClosed(WindowEvent e) {}
    public void windowClosing(WindowEvent e)
    { System.out.println("Closing");
      System.exit(0); }
    public window_watcher() {} }
    
  private class button_watcher implements ActionListener
  { public void actionPerformed(ActionEvent e)
    { Object o=e.getSource();
      if (o==clear)
      { t1.setText("0");
        t2.setText("0");
        record.setText(""); }
      if (o==doit)
      { String text1=t1.getText();
        String text2=t2.getText();
        String op="";
        int int1=0, int2=0, answer=0;
        boolean ok=true;
        try
        { int1=Integer.parseInt(text1); }
        catch (NumberFormatException ee)
        { t1.setText(text1+": BAD!");
          ok=false; }
        try
        { int2=Integer.parseInt(text2); }
        catch (NumberFormatException ee)
        { t2.setText(text2+": BAD!");
          ok=false; }
        if (ok)
        { Checkbox whichop=cbg.getSelectedCheckbox();
          if (whichop==cbadd)
          { answer=int1+int2;
            op="+"; }
          else if (whichop==cbsub)
          { answer=int1-int2;
            op="-"; }
          else if (whichop==cbmul)
          { answer=int1*int2;
            op="x"; }
          else if (whichop==cbdiv)
          { if (int2==0)
              ok=false;
            else
              answer=int1/int2;
            op="/"; }
          if (ok)
            record.append("\n"+text1+op+text2+"="+answer);
          else
            record.append("\n"+text1+op+text2+"= BAD!"); } } }
    public button_watcher() {} }
    
  private TextField t1, t2;
  private CheckboxGroup cbg;
  private Checkbox cbadd, cbsub, cbmul, cbdiv;
  private Button doit, clear;
  private TextArea record;
  
  public thing()
  { Frame f=new Frame("thing");
    f.addWindowListener(new window_watcher());
    Panel p=new Panel();
    p.setLayout(null);
    p.setSize(250,470);
    f.add(p);
    
    Label l1=new Label("First Operand");
    l1.setBounds(20,20,100,20);
    p.add(l1);
    t1=new TextField("0");
    t1.setBounds(20,45,200,20);
    p.add(t1);
    
    Label l2=new Label("Second Operand");
    l2.setBounds(20,70,100,20);
    p.add(l2);
    t2=new TextField("0");
    t2.setBounds(20,95,200,20);
    p.add(t2);
    
    Label l3=new Label("Operation");
    l3.setBounds(20,120,100,20);
    p.add(l3);
    cbg=new CheckboxGroup();
    cbadd=new Checkbox("Add",true,cbg);
    cbadd.setBounds(45,145,100,20);
    p.add(cbadd);
    cbsub=new Checkbox("Subtract",false,cbg);
    cbsub.setBounds(45,170,100,20);
    p.add(cbsub);
    cbmul=new Checkbox("Multiply",false,cbg);
    cbmul.setBounds(45,195,100,20);
    p.add(cbmul);
    cbdiv=new Checkbox("Divide",false,cbg);
    cbdiv.setBounds(45,220,100,20);
    p.add(cbdiv);
    
    button_watcher buttoneer=new button_watcher();
    doit=new Button("Do It");
    doit.setBounds(45,250,50,20);
    doit.addActionListener(buttoneer);
    p.add(doit);
    clear=new Button("Clear");
    clear.setBounds(145,250,50,20);
    clear.addActionListener(buttoneer);
    p.add(clear);
    
    Label l4=new Label("Record");
    l4.setBounds(20,280,100,20);
    p.add(l4);
    record=new TextArea("Hello!",30,100);
    record.setBounds(20,300,200,150);
    p.add(record);
    
    f.pack();
    f.show(); } }