public abstract class TwoPlayerGame
{   public static final int PLAYER_ONE = 1;
     public static final int PLAYER_TWO = 2;

     private boolean onePlaysNext = true;

     public void setPlayer(int starter)
     {   if (starter == PLAYER_TWO)
             onePlaysNext = false;
         else onePlaysNext = true;
     } //setPlayer()

     public int getPlayer()
     {   if (onePlaysNext) return PLAYER_ONE;
         else return PLAYER_TWO;
     } //getPlayer()

     public void changePlayer()
     {   onePlaysNext = !onePlaysNext;
     } //changePlayer

     public String getRules() {
         return "The rules of this game are: ";
     }
     public abstract boolean gameOver();
     public abstract int getWinner();

     public abstract String report();
     public abstract String move (String s);
     public abstract String prompt();
} //TwoPlayerGame