Craps.java

import java.util.Random;


/**
* Simulates the game of craps. A modified version of Owen Astrachan's
* program, A Computer Science Tapestry, 1997, McGraw-Hill, p. 225-231.
* Revised on 4/10/97, Cary Matsuoka.
* Converted to Java on 6/2/2002, George Peck.
* Modified 1/19/06 Jason Quesenberry and Nancy Quesenberry.
*
*/
public class Craps
{
  private Random myDie;
  private int myGamesWon, myGamesToPlay;
  private double myPercentWon;

  /**
   * Constructor for the Craps object
   */
  public Craps()
  {
    myDie = new Random();
  }

  /**
   * Plays craps the specified number of times and evaluates
   * the number of games won and winning percentage
   *
   * @param gamesToPlay Number of trials (games)
   */
  public void playGame(int gamesToPlay)
  {
    myGamesToPlay = gamesToPlay;
    myGamesWon = 0;
    for ( int game = 0; game < myGamesToPlay; game++ )
    {
      if (winGame())
      {
        myGamesWon++;
      }
    }
    myPercentWon = (double) myGamesWon / myGamesToPlay * 100;
  }

  /**
   * Description of the Method
   *
   * @return Total number of games won
   */
  public int gamesWon()
  {
    return myGamesWon;
  }

  /**
   * Description of the Method
   *
   * @return Winning percentage
   */
  public double percentWon()
  {
    return myPercentWon;
  }

  /**
   * Gets the point attribute of the Craps object
   *
   * @param point Value to match, 2 <= point <= 12
   * @return true if point is matched, false if 7 is rolled first
   */
  private boolean getPoint(int point)
  {// precondition: 2 <= point <= 12
    int sum;
    do
    {
      sum = rollDice();
    } while ((sum != point) && (sum != 7));  // <--- application of DeMorgan's Laws
/*
        if (sum == point)
          System.out.println("point is matched, player won");
        else
          System.out.println("crapped out");
*/
    return (sum == point);
  }

  /**
   * Determines if a single game of craps is won or lost
   *
   * @return true if a single game of craps is won, otherwise false
   */
  private boolean winGame()
  {
    int point = rollDice();

    switch (point)
    {
        case 7:
        case 11:
          // System.out.println("7 or 11 rolled, win");
          return true;
        case 2:
        case 3:
        case 12:
          // System.out.println("2, 3,or 12 rolled, lost");
          return false;
        default:
          return getPoint(point);
    }
  }

  /**
   * Simulates the rolling of two dice
   *
   * @return sum of rolling two dice
   */
  private int rollDice()
  {
    int first = myDie.nextInt(6) + 1;
    int second = myDie.nextInt(6) + 1;
    int sum = first + second;
    return sum;
  }

}