(PHP 4 >= 4.0.4, PHP 5)
gmp_fact — Factorial
Calculates factorial (a!) of a .
The factorial number.
It can be either a GMP number resource, or a numeric string given that it is possible to convert the latter to a number.
A GMP number resource.
Example #1 gmp_fact() example
<?php
$fact1 = gmp_fact(5); // 5 * 4 * 3 * 2 * 1
echo gmp_strval($fact1) . "\n";
$fact2 = gmp_fact(50); // 50 * 49 * 48, ... etc
echo gmp_strval($fact2) . "\n";
?>
上例将输出：
120 30414093201713378043612608166064768844377641568960512000000000000