PHP Manual: Factorial

Description

GMP gmp_fact(GMPintstring $num)

Calculates factorial (num!) of num.

Parameters

num

The factorial number.

A GMP object, an int, or a string that can be interpreted as a number following the same logic as if the string was used in gmp_init with automatic base detection (i.e. when base is equal to 0).

Return Values

A GMP object.

Examples

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";
?>

The above example will output:

120
30414093201713378043612608166064768844377641568960512000000000000