[Marcus]

Hello, I am writing a program that plays 1000 games of craps then prints out win, loss, the amt of rolls for each game, the odds of winning and losing. I am getting the following error:

Code:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 22
at chapt7.Craps.play(Craps.java:94)
at chapt7.Craps.main(Craps.java:17)

I have been over this numerous times and can't seem to figure out the issue, here is my code.

Code:

package chapt7;

// Craps class simulates the dice game craps.
import java.util.Random;

public class Craps 
{
	public static void main(String[] args)
	{
		int whenWin[] = new int[22]; //array to store number of rolls that it takes to win each game
		 							 //whenWin[0] not used, more than 20 rolls counts is stored in whenWin[21]
		int whenLose[] = new int[22]; //array to store number of rolls that it takes to lose each game
									  //whenLose[0] not used, more than 20 rolls counts is stored in whenLose[21]
		
		//plays 1000 games of craps
		for (int i = 0; i < 1000; i++)
			play(whenWin, whenLose);
		//1000 games complete
		
		//prints out the amount of times game was won on the 'j'th roll
		for (int j = 1; j < 22; j++)
		{
			if (j == 21)
				System.out.printf("The amount of times won after roll %d is %d\n", j, whenWin[j]);
			else
				System.out.printf("The amount of times won on roll %d is %d\n", j, whenWin[j]);
		} //end for loop
		
		//prints out the amount of times game was lost on the 'j'th roll
		for (int j = 1; j < 22; j++)
		{
			if (j == 21)
				System.out.printf("The amount of times lost after roll %d is %d\n", j, whenLose[j]);
		
			else
				System.out.printf("The amount of times lost on roll %d is %d\n", j, whenLose[j]);
		} //end for loop
		
		chances(whenWin, whenLose); //caculates and prints out craps chances
		avgLengthGame(whenWin, whenLose); //calculates and prints out avg number of rolls/game
		
	}//end main
	
	
	// create random number generator for use in method rollDice
	private static Random randomNumbers = new Random(); 
  
	// enumeration with constants that represent the game status
	private enum Status { CONTINUE, WON, LOST };                
  
	// constants that represent common rolls of the dice
	private final static int SNAKE_EYES = 2;
	private final static int TREY = 3;      
	private final static int SEVEN = 7;     
	private final static int YO_LEVEN = 11; 
	private final static int BOX_CARS = 12; 
  
	// plays one game of craps
	public static void play(int[] whenWin, int[] whenLose)
	{
		int myPoint = 0; // point if no win or loss on first roll
		Status gameStatus; // can contain CONTINUE, WON or LOST
        int rollCount = 1; //counts # of rolls
        int sumOfDice = rollDice(); // first roll of the dice
        // determine game status and point based on first roll 
        switch ( sumOfDice ) 
        {
           case SEVEN: // win with 7 on first roll    
           case YO_LEVEN: // win with 11 on first roll
        	   gameStatus = Status.WON;
        	   whenWin[rollCount]++;
        	   break;
           case SNAKE_EYES: // lose with 2 on first roll
           case TREY: // lose with 3 on first roll      
           case BOX_CARS: // lose with 12 on first roll 
              gameStatus = Status.LOST;
              whenLose[rollCount]++;
              break;
           default: // did not win or lose, so remember point
              gameStatus = Status.CONTINUE; // game is not over
              myPoint = sumOfDice; // remember the point
              break; // optional at end of switch
        } // end switch 
  
        // while game is not complete
        while ( gameStatus == Status.CONTINUE ) // not WON or LOST
        { 
           sumOfDice = rollDice(); // roll dice again
           rollCount++;
           // determine game status
           if ( sumOfDice == myPoint ) // win by making point
           {
        	   		gameStatus = Status.WON;
        	   		whenWin[rollCount]++;
           }
           else
           {   
              if ( sumOfDice == SEVEN ) // lose by rolling 7 before point
              {	  
            	  	gameStatus = Status.LOST;
              		whenLose[rollCount]++;
              }
           }
        } // end while 
  
     } // end method play
  
     // roll dice, calculate sum and display results
     public static int rollDice()
     {
        // pick random die values
        int die1 = 1 + randomNumbers.nextInt( 6 ); // first die roll
        int die2 = 1 + randomNumbers.nextInt( 6 ); // second die roll
  
        int sum = die1 + die2; // sum of die values
        
        return sum; // return sum of dice
     } // end method rollDice
     
     //determines chances of wining craps
     public static int chances(int[] win, int[] lose)
     {
    	 int w = 0; //counts the number games won
    	 int l = 0; //counts the number games lost
    	 for (int i =1; i < 22; i++)
    	 {
    		 w = w + win[i];
    		 l = l + lose[l];
    	 }
    	 System.out.printf("The Chances of winning craps is %d:%d\n", w/w, l/w);
    	 return 0;	 
     }//end method chances
     
     //calculates the average length of each game, i.e. avg amt of rolls to win or lose
     public static int avgLengthGame(int[] win, int[] lose)
     {
    	 int numOfRolls = 0;
    	 int avg = 0;
    	 for (int i =1; i < 22; i++)
    	 {
    		 numOfRolls = numOfRolls + (win[i] * i) + (lose[i] * i);
    	 }
    	 avg = numOfRolls/1000;
    	 System.out.printf("The Average number of rolls per game is %d\n", avg);
    	 return 0;
     }//end method avgLengthGame
     
  } // end class Craps

I am using eclipse, if that is of any help? Thanks

Marcus