/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*- */
/**************************************************************************
* Copyright (C) DMGualtieri 2010
*
* picalc is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Picalc is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see .
**************************************************************************/
#include
#include
#include
#include
long int trials;
long int drops;
long int i;
long int j;
double x;
double y;
double r;
double count;
FILE *outdata;
/* Determination of pi by random dots in a unit circle
This is essentially a Monte Carlo calculation. We draw a circle in a square,
we drop grains of sand onto them and count how many land inside the circle.
Since the area of the square is 1 (if its sides are one), and the area of the
circle is (pi/4), then pi is four times the ratio of the number of grains
that land inside the circle to the total number of grains.
*/
int main(int argc, char *argv[])
{
if (argc<2)
{
printf("Usage: picalc number_of_grain_drops_per_trial number_of_trials\n");
exit(1);
}
//Seed random number generator
srand ( (unsigned)time ( NULL ) );
//Open output datafile
if ((outdata = fopen("pi_data.txt","w"))==NULL)
{printf ("\nOutput file cannot be opened.\n");
exit (1);}
else
{
printf("Output file = pi_data.txt");
}
drops = atol(argv[1]);
trials = atol(argv[2]);
/* It's always good to check RAND_MAX to see how many random numbers we can
extract without a problem */
printf("\nTrials = %ld Drops = %ld Rand_Max = %d\n",trials,drops,RAND_MAX);
for(j=0;j