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

public class Test1a extends java.applet.Applet 
   {

  CheckboxGroup cbg;
  Checkbox Box0, Box1, Box2, Box3, Box4;
  Button Check;
  Label Response;

  public void init() {

    setBackground(new Color(200,200,200));
    setLayout(new FlowLayout(FlowLayout.LEFT));
    cbg = new CheckboxGroup();

    Box0 = new Checkbox("Up", cbg, true);
    add(Box0);
    Box1 = new Checkbox("Down", cbg, false);
    add(Box1);
    Box2 = new Checkbox("Left", cbg, false);
    add(Box2);
    Box3 = new Checkbox("Right", cbg, false);
    add(Box3);
    Box4 = new Checkbox("The field is zero", cbg, false);
    add(Box4);
    // Check button
    Check = new Button("Check Answer");
    add(Check);

    Response = new Label("Choose the answer you think is correct", Label.CENTER);
    add(Response);

  }

  public boolean action (Event evt, Object arg) {

    if (evt.target instanceof Button) {
      if (cbg.getCurrent().equals(Box2)) {
        Response.setText("Correct!");
      }
      else {
        Response.setText("Sorry, that's not correct.");
      }
    }
    else return super.action(evt, arg);
    return true;
  }
}