Game of Life

gistfile1.txt

<?php

define('LIFE', '+');
define('VOID', ' ');

define('MAX_X', $argv[1]);
define('MAX_Y', $argv[2]);

$world = genWorld(MAX_X, MAX_Y);

while(true)
{
	$world = draw($world);
	$world = update($world);

	usleep(0.5 * 1000 * 1000);
}

function genWorld()
{
	$world = array();

	for($x = 0; $x < MAX_X; $x++)
	{
		for($y = 0; $y < MAX_Y; $y++)
		{
			$world[$x][$y] = VOID;
		}
	}

	for($i = 0; $i < MAX_X * MAX_Y * 0.25; $i++)
	{
		$world[rand(0, MAX_X)][rand(0, MAX_Y)] = LIFE;
	}

	return $world;
}

function update($world)
{
	$toFill = [];
	$toKill = [];

	for($x = 0; $x < MAX_X; $x++)
	{
		for($y = 0; $y < MAX_Y; $y++)
		{
			$neighbors = countNeighbors($world, $x, $y);

			if($world[$x][$y] == LIFE)
			{
				if ($neighbors < 2 OR $neighbors > 3 )
				{
					$toKill[] = array($x, $y);
				}
			}
			else
			{
				if($neighbors == 3)
				{
					$toFill[] = array($x, $y);
				}
			}
		}
	}

	foreach($toFill as $ent)
	{
		$world[$ent[0]][$ent[1]] = LIFE;
	}

	foreach($toKill as $ent)
	{
		$world[$ent[0]][$ent[1]] = VOID;
	}

	return $world;
}

function draw($world)
{
	for($x = 0; $x < MAX_X; $x++)
	{
		for($y = 0; $y < MAX_Y; $y++)
		{
			echo ' '.$world[$x][$y];
		}

		echo PHP_EOL;
	}

	return $world;
}

function countNeighbors($world, $x, $y)
{
	$count = 0;

	for($a = $x - 1; $a <= $x + 1; $a++)
	{
		for($b = $y - 1; $b <= $y + 1; $b++)
		{
			if($a == $x AND $b == $y) continue;

			if(isset($world[$a][$b]) AND $world[$a][$b] == LIFE)
				$count++;
		}
	}

	return $count;
}

function fillAround($world, $x, $y, $with = LIFE)
{
	for($a = $x - 1; $a <= $x + 1 AND $a <= MAX_X; $a++)
	{
		for($b = $y - 1; $b <= $y + 1 AND $b <= MAX_Y; $b++)
		{
			if($a == $x AND $b == $y) continue;

			$world[$a][$b] = $with;
		}
	}

	return $world;
}

run with eg php gameoflife.php 100 100