function prime_factors($x)
{
echo "<center>";
$primes = primes_to($x);
if (in_array($x, $primes)) {
return array("{$x} is a prime number itself, and therefore can't be created by multiplying other prime numbers.");
} else {
echo "<p>If you multiply all the following numbers together, you get {$x}:</p>";
$factors = array();
$count = count($primes) - 1;
$c = 0;
while ($x > 1) {
if ($x % $primes[$c] == 0) {
$factors[] = $primes[$c];
$x /= $primes[$c];
} else {
$c++;
}
}
// end while
}
// end else
return $factors;
}
<?php
include_once 'primefunctions.php';
$input = $_POST['input'];
$title = "All primes up to {$input}";
include_once 'header.php';
echo "<center><h1>{$title}</h1>";
if ($input > 20000) {
echo "<p>That's a really big number! Are you really sure you need all those primes? What are you planning to do with them?</p>";
} else {
echo "<p>";
$primes = primes_to($input);
$i = 0;
foreach ($primes as $prime) {
echo "{$prime} ";
$i++;
if ($i == 10) {
$i = 0;
echo "<br />";
}
}
echo "</p>";
}
echo "<p><a href='index.php'>Return to main page</a></p>";
