/**
   Simulate a coin with two faces, head and tail.
*/
public class Coin
{
   public Coin () { flip(); }

   /**
      Flip the coin.
   */
   public void flip () { face = Math.random() > 0.5 ? HEADS : TAILS; }
   public int getFace() { return face; }

   public static final int HEADS = 1;
   public static final int TAILS = 0;

   private int face;
}