#!/usr/bin/perl
# This is a quick program to calculate pi using the Monte Carlo method.
# I recomend inputting  a value for $cycles greater that 1000. 
# I am working on a detailed explanation of how and why this works. 
# I will add it as soon as I'm done.
use strict;
open(PI, ">>pi.dat") || die "pi.dat";
my ($i, $j, $yespi, $pi) = 1;
my $cycles = 1;
srand;
while ($j <= 100000) {
    $cycles = $j;
    while ($i <= $cycles) {
	my ($x, $y, $cdnt) = 1;
	$x = rand;
	$y = rand;
	$cdnt = $x**2 + $y**2;
	if ($cdnt <= 1) {
	    ++$yespi;
	}    
    $i=$i + 10;
    $pi = ($yespi / ($cycles / 10)) * 4; # since I add 10 every time.
    print PI "$cycles $pi\n";
    }
$j = $j + 10;
}
close(PI) || die "pi.dat";