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prime numbers

function to check wether a number is a prime number or not.
returns TRUE if number given is a prime number and FALSE if not.

function is_prime( ) [ line 3 ]

full source of prime numbers [ line 1 - 22 ] | download prime numbers

1	<?php
2	// is_prime(number) checks if a number is a prime number or not
3	function is_prime($i)
4	{
5	if($i % 2 != 1) return false;
6	$d = 3;
7	$x = sqrt($i);
8	while ($i % $d != 0 && $d < $x) $d += 2;
9	return (($i % $d == 0 && $i != $d) * 1) == 0 ? true : false;
10	}
11	// example: show all prime numbers between $start and $end
12	$start = 0;
13	$end = 1000;
14	for($i = $start; $i <= $end; $i++)
15	{
16	if(is_prime($i))
17	{
18	echo '
19	'.$i.' ';
20	}
21	}
22	?>

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