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PHP srand() Function

Complete PHP Math Reference

Definition and Usage

The srand() function seeds the random number generator for rand().

This function should be called only once per script, and it must be called before any calls to rand().

Syntax

srand(seed)

Parameter	Description
seed	Optional. Seed number for the random number generator. If omitted, a random value is used.

Tips and Notes

Note: In PHP 4.2.0 and later, there is no need to seed the random generator with srand(). This is done automatically.

Tip: The greater the randomness of the seed, the more random number you'll get. A suitable number to seed this function with, is mktime().

Example

In this example we will seed the random number generator:

<?php
srand(mktime());
echo(rand());
?>

The output of the code above could be:

14054