/***********************************************
**
** proj4.c -- rolling dice
**
** D. L. Frey
** 1/4/99
**
**  This program simulates rolling a pair of dice 300 times
**  It counts the number of times each differet face (1-6)
**  occurs and the number of times each total (2-12) occurrs
**
** Algorithm
**
**
** Notes--
**	1. the array 'count' is defined with size 7 so
** that the code can use indexes 1-6, the values on the
** faces of the dice.  count[0] is not
used.
**	2. the array 'total' is defined with size 13 so
** that the code can use indexes 2-12, the possible totals
** of the 2 dice.  total[0] and total[1] are not used
***********************************************************/

#include <stdio.h>
#include <math.h>
#include <time.h>


#define ROLLS 300	/* number of rolls of the dice */
#define SEED 44		/* random number seed */

/* prototypes for subroutines */
void printCounts (int a[], int size);
void printHistogram (int b[]);

main()
{
  /* define arrays to hold counts -- initialized to zero */
  int count[7] = {0};
  int total[13] = {0};

  int i,j , die1, die2;

  /* initialize the random number generator */
  srand (SEED);

  /* roll the dice ROLLS times
  ** 1 + rand() % 6 yields an integer between
  ** 1 and 6, inclusive
  */
  for (i = 0; i < ROLLS; i++)
  {
    /* increment count for first die */
    die1 = 1 + (rand() % 6);
    count[die1]++;

    /* increment count for secnd die */
    die2 = 1 + (rand() % 6);
    count[die2]++;

    /* increment the count for the total
    ** of the two dice
    */
    total[die1 + die2]++;
  }

  /* call the subroutine printCounts
  ** to print the contents of the array 'count'
  */
  printCounts (count, ROLLS);


  /* print historgram for total */
  printHistogram (total);

}

/**************************************
** function printCount
**
** Inputs
**	a -- an integer array
**	size -- the total of all elements in a
** Outputs
**	displays the contents of 'a' on the screen
***************************************/

void printCounts (int a[], int size)
{
  int i;

  /* print the counts */
  printf ("In %d rolls of two dice:\n", size);
  printf ("Die       Occurrences       Percentage\n");
  for (i = 1; i < 7; i++)
  {
    printf ("%2d             %3d            %0.2f\n", 
	i, a[i], ((float)a[i] / (size * 2)) * 100);
  }

}


/******************************************
** subroutine printHistogram
**
** this subroutine prints a historgram
** using a * to represent each occurrence of
** the total of two dice
**
** Input -- an integer array that is assumed
**   to contain the dice totals
** Output -- histogram printed on the screen
*****************************************/
void printHistogram (int b[])
{
  int i, j;
  printf ("The sum of the dice were:\n");

  /* for each possible total.. */
  for (i = 2; i < 13; i++)
  {
    /* print readable total */
    printf ("%2d occurred %3d times: ", i, b[i]);

    /* print a * for each time that total occurred */
    for (j = 0; j < b[i]; j++)
    {
	printf ("*");
    }

    /* go to the next line */
    printf ("\n");
  }
}