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>";