1: 2: public class PlayCircleDemo 3: { 4: public static void main(String[] args) 5: { 6: PlayCircle circle = new PlayCircle( ); 7: circle.setDiameter(2); 8: System.out.println("If circle has diameter 2,"); 9: circle.showArea( ); 10: System.out.println("Now you choose the diameter:"); 11: PlayCircle.areaDialog( ); 12: } 13: }