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srand

Name

srand — Seeds the random number generator with the given argument.

Synopsis

void srand(seed); int seed: Seed value

Returns

Nothing

Description

Seeds the random number generator. It's always a good idea to do this before using the rand() function. Any number can be used to seed the generator, but as a general rule the more random the number you start with, the more random the number you'll get. Usually, using something like mktime() yields a suitable number. Another common solution is to combine process IDs, the time, and the client's IP number to produce a more random seed.

Version

PHP 3, PHP 4

Example

Example 693. Seed the random number generator

srand(mktime());
echo "A random number: ", rand();

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PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing (Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch). This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). The authors of this book have elected not to choose any options under the OPL. This online book was obtained from http://www.fooassociates.com/phpfer/ and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4 for the most part. The information is provided on an as-is basis, and no warranty or fitness is implied. All persons and entities shall have neither liability nor responsibility to any person or entity with respect to any loss or damage arising from the information contained in this book.