import java.awt.*; 
import java.applet.Applet;

public class RadioApplet extends Applet {
  CheckboxGroup group = new CheckboxGroup();
  Checkbox cb[] = new Checkbox[4];
  
  public void init() {
    cb[0] = new Checkbox("English", group, true);
    cb[1] = new Checkbox("Mathematics", group, false);
    cb[2] = new Checkbox("Physics", group, false);
    cb[3] = new Checkbox("History", group, false);
    
    for (int i = 0; i < 4; ++i ) add(cb[i]);
  }
  
  public boolean action(Event evt, Object obj) {

    if(evt.target instanceof Checkbox) {
        for (int i = 0; i < 4; ++i ) {
            if ( evt.target == cb[i] ) {
                System.out.println("Checkbox No."+i);
                System.out.println("State is "+cb[i].getState());
                break;
            }
        }
    }
    else {
      System.out.println("Not a Checkbox event.");
    }
    return true;
  }

}