//example 8-3
import java.applet.Applet;
import java.awt.*;
public class tt extends Applet
{
   Button btnExit=new Button("Exit");
   Button btnRun=new Button("Run");
   Label lblIntro=new Label("Please input positive integer here");
   Label lblResult=new Label("The result is:");
   TextField txtIntro=new TextField("0",10);
   TextField txtResult=new TextField("0",10);
   Panel p1=new Panel();
   Panel p2=new Panel();
   Panel p3=new Panel();
   public void init()
   {
   	 resize(350,200);
   	 p1.add(lblIntro);p1.add(txtIntro);
   	 p2.add(lblResult);p2.add(txtResult);
   	 p3.add(btnExit);p3.add(btnRun);
   	 add("North",p1);add("Center",p2);add("South",p3);
   }
   public boolean action(Event evt,Object obj)
   {
   	  if(evt.target instanceof Button)
   	  {
   	  	 String btnName=(String)obj;
   	  	 if(btnName.equals("Exit"))
   	  	   System.exit(0);
   	  	 else
   	  	 {
   	  	    int sum=0;
   	  	    for(int i=1;i<=Integer.parseInt(txtIntro.getText());i++)
   	  	       sum=sum+i;
   	  	    txtResult.setText(String.valueOf(sum));
   	  	 }
   	  }
   	  return super.action(evt,obj);
   }
   public static void main(String args[])
   {
   	 new ttFrame(new tt());
   }
}

class ttFrame extends Frame
{
   public ttFrame(Applet applet)
   {
      resize(400,400);add("Center",applet);
      applet.init();
      show();
   }
   public boolean handle(Event evt)
   {
      if(evt.id==Event.WINDOW_DEICONIFY)
         System.exit(0);
      return super.handleEvent(evt);
   }
}