Dice Simualtion

This is a discussion on Dice Simualtion within the C Programming forums, part of the General Programming Boards category; I am trying to make a simple simulator for dice rolls. The program needs the following parms. 1) The NUMBER ...

  1. #1
    Registered User
    Join Date
    Apr 2008
    Posts
    32

    Dice Simualtion

    I am trying to make a simple simulator for dice rolls. The program needs the following parms. 1) The NUMBER of dice to roll. 2) The number of FACES on each dice. 3) Lastly, it needs how many simulations to walk through (COUNT). Either I let the user take the default or they need to enter the parms when starting the program.

    The code is kind of slow to execute and I am wondering if I did something really foolish. I have never write a simulation program like this before. Any suggestion would be helpful.

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    
    int main(long argc, char *argv[])
    {
            unsigned long a = 0, b = 0, number = 0;
            long stime = 0, ltime = 0;
            unsigned long *dice, *numbers, COUNT, NUMBER, FACES = 6, TOTAL;
    
            
            if ( argc == 4 )//Did they want to define all parms
            {
                    COUNT   = atol(argv[1]);
                    NUMBER  = atol(argv[2]); 
                    FACES   = atol(argv[3]);
            }
            else if ( argc == 3 )//Did they want to define sim count and number of die, but defaulted to only 6 faces
            {
                    COUNT   = atol(argv[1]);
                    NUMBER  = atol(argv[2]);
                    FACES   = 6;
            }
            else if ( argc == 2 )//Default to only 6 Faces on the dice and roll 1 dice, but let they set sim count
            {
                    COUNT   = atol(argv[1]);
                    NUMBER  = 1;
                    FACES   = 6;
            }
            else if ( argc == 1 )//Default 100 sims, 1 dice, and use a 6 sided die. 
            {
                    COUNT   = 100;
                    NUMBER  = 1;
                    FACES   = 6;
            }
            else // They have used too many parms
            {
                    fprintf(stderr, "\nUsage: %s [COUNT] [NUMBER] [FACES]\n\n", argv[0]);
                    exit(1);
            }
    
            //Seed for Random Numbers 
            ltime = time(NULL);
            stime = (unsigned) (ltime)/2;
            srand(stime);
    
            //Determine total options or max rolled number
            TOTAL = FACES*NUMBER;
    
            //Create memory for needed dices
            dice = malloc((NUMBER) * sizeof(NUMBER)) ;
            if (!dice)
            {
                    fprintf(stderr, "Memory Allocation Error\n");
                    exit(2);
            } 
            else
            {
                    //Set Dice Faces to Zero 
                    for ( a = 0; a < (NUMBER); a++)
                    {
                            dice[a] = 0;
                    }
            } 
    
            //Create memory for Sum of dice counts
            numbers = malloc( (TOTAL) * sizeof(long) );
            if (!numbers)
            {
                    fprintf(stderr, "Memory Allocation Error\n");
                    exit(2);
            } 
            else
            {
                    //Set number aggrate to 0 all around
                    for ( a = 0; a <= (TOTAL); a++)
                    {
                            numbers[a] = 0;
                    }
            } 
     
            //Start running sim for COUNT Rolls
            for (a = 1; a <= COUNT; a++)
            {
                    //Roll the dice
                    number = 0;
                    for (b = 0; b < NUMBER; b++)
                    {
                            dice[b] = (unsigned long) (rand() % FACES) + 1;
                            number = number + dice[b];
                    }
                    //Count the rolls totals
                    for (b = 1; b <= TOTAL; b++)
                    {
                            if ( number == b )
                            {
                                    numbers[b]++;
                            }
                    }
                    //Show every millionth sim
                    if ( a % 1000000 == 0 )
                    {
                            fprintf(stderr, "%ld\n", a);
                    }
            }
            
            //Display totals 
            for (b = NUMBER; b <= TOTAL; b++)
                    printf("%-20ld %-20ld %%%-20.2f\n", b, numbers[b], 
                    (float) numbers[b]/COUNT*100);
    
            return 0;
    }

  2. #2
    and the hat of wrongness Salem's Avatar
    Join Date
    Aug 2001
    Location
    The edge of the known universe
    Posts
    32,548
    Writing to stdout is usually pretty slow just to give people a vague chance of seeing what's going on.

    Try
    myprog > results.txt
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  3. #3
    Registered User
    Join Date
    Apr 2008
    Posts
    32
    hehehe, that is why I set the junk output to go to stderr... So I could send the real data to a file.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Newbie class question
    By vastgoten in forum C++ Programming
    Replies: 4
    Last Post: 07-31-2008, 01:43 AM
  2. Dice Roller
    By Bobnine in forum C Programming
    Replies: 3
    Last Post: 05-19-2008, 09:45 PM
  3. Replies: 9
    Last Post: 11-11-2007, 01:31 PM
  4. craps game & dice game..
    By cgurl05 in forum C Programming
    Replies: 3
    Last Post: 03-25-2006, 06:58 PM
  5. Dice Rolling Program help
    By courtesan in forum C Programming
    Replies: 3
    Last Post: 08-17-2005, 03:14 PM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21