import java.applet.*;import java.awt.*;public class Coin extends Applet{int numCoins=3; Rectangle[] coins=new Rectangle[numCoins]; Rectangle[] slots=new Rectangle[numCoins]; Color[] colors={Color.red,Color.green,Color.blue}; Image bbuf; Graphics bbufG; int dragging=-1; Point offset;  public void init() {for(int i=0;i<numCoins;i++)  {coins[i]=new Rectangle(rand(50),rand(50),50, 50);   slots[i]=new Rectangle();  } }   public int rand(int r) {return (int)Math.floor(Math.random()*r); }   public void paint(Graphics g) {update(g); }  public void update(Graphics g) {int w=size().width;  int h=size().height;  if(bbuf==null||w>bbuf.getWidth(null)||h>bbuf.getHeight(null))  {bbuf=createImage(w,h);   bbufG=bbuf.getGraphics();  }  bbufG.setColor(Color.gray);  bbufG.fillRect(0, 0,size().width, size().height);  for(int i=0;i<numCoins;i++)  {slots[i].reshape(i*w/3,h-30,w/3, 30);   slots[i].grow(-5, -2);   bbufG.setColor(colors[i]);   bbufG.fillRect(slots[i].x,slots[i].y,slots[i].width,slots[i].height);  }  for(int i=0;i<numCoins;i++)  {if(!coins[i].isEmpty())   {if(dragging==i&&coins[i].intersects(slots[i]))    {bbufG.setColor(Color.black);    }    else    {bbufG.setColor(colors[i]);    }    bbufG.fillOval(coins[i].x,coins[i].y,coins[i].width, coins[i].height);   }  }  g.drawImage(bbuf,0,0,this); }      public synchronized boolean mouseDown(Event evt, int x, int y)  {for(int i=coins.length-1;i>=0;i--)   {if(!coins[i].isEmpty()&&coins[i].inside(x, y))    {dragging=i;     offset=new Point(coins[i].x-x,coins[i].y-y);     return true;    }   }   return false;  }      public synchronized boolean mouseDrag(Event evt,int x, int y)  {if(dragging>=0)   {coins[dragging].move(x, y);    coins[dragging].translate(offset.x,offset.y);    repaint();    return true;   }   return false;  }    public synchronized boolean mouseUp(Event evt,int x,int y)  {if(dragging>=0)   {if(coins[dragging].intersects(slots[dragging]))    { coins[dragging].width=0;    dragging=-1;    }   repaint();   return true;  }  return false;  } }