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

public class PlayBalloon extends Applet implements ActionListener
{
        private Button grow, shrink;
        private Balloon myBalloon;

        public void init()
        {
                grow = new Button("Grow");
                add(grow);
                grow.addActionListener(this);

                shrink = new Button("Shrink");
                add(shrink);
                shrink.addActionListener(this);

                myBalloon = new Balloon(20,50,50);
        }

        public void actionPerformed(ActionEvent event)
        {
                if(event.getSource()==grow)
                  myBalloon.changeSize(10);
                if(event.getSource()==shrink)
                  myBalloon.changeSize(-10);
                repaint();

        }

        public void paint(Graphics g)
        {
                myBalloon.display(g);
        }
}

class Balloon
{
        private int diameter;
        private int xCoord, yCoord;

        public Balloon (int initialDiameter,int initialX, int initialY)
        {
                diameter = initialDiameter;
                xCoord = initialX;
                yCoord = initialY;
        }

        public void changeSize(int change)
        {
                diameter = diameter+change;
        }

        public void display(Graphics g)
        {
                g.drawOval(xCoord,yCoord,diameter,diameter);
        }
}