php-doc-en/reference/math/functions/mt-rand.xml
Mehdi Achour e62b27dd06 Added title to examples
wrapped the see also lines (make it easy to translate)


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@153341 c90b9560-bf6c-de11-be94-00142212c4b1
2004-03-10 14:39:13 +00:00

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XML

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.9 $ -->
<!-- splitted from ./en/functions/math.xml, last change in rev 1.2 -->
<refentry id="function.mt-rand">
<refnamediv>
<refname>mt_rand</refname>
<refpurpose>Generate a better random value</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<methodsynopsis>
<type>int</type><methodname>mt_rand</methodname>
<methodparam choice="opt"><type>int</type><parameter>min</parameter></methodparam>
<methodparam><type>int</type><parameter>max</parameter></methodparam>
</methodsynopsis>
<simpara>
Many random number generators of older libcs have dubious or
unknown characteristics and are slow. By default, PHP uses the
libc random number generator with the <function>rand</function>
function. The <function>mt_rand</function> function is a drop-in
replacement for this. It uses a random number generator with
known characteristics using the <ulink url="&url.mersenne;">
Mersenne Twister</ulink>, which will produce random numbers four times
faster than what the average libc rand() provides.
</simpara>
<simpara>
If called without the optional <parameter>min</parameter>,
<parameter>max</parameter> arguments <function>mt_rand</function>
returns a pseudo-random value between 0 and
<constant>RAND_MAX</constant>. If you want a random number
between 5 and 15 (inclusive), for example, use <literal>mt_rand
(5, 15)</literal>.
</simpara>
<para>
<example>
<title><function>mt_rand</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
echo mt_rand() . "\n";
echo mt_rand() . "\n";
echo mt_rand(5, 15);
?>
]]>
</programlisting>
<para>
The above example will output something similar to:
</para>
<screen>
<![CDATA[
1604716014
1478613278
6
]]>
</screen>
</example>
</para>
&note.randomseed;
<note>
<para>
In versions before 3.0.7 the meaning of
<parameter>max</parameter> was <parameter>range</parameter>. To
get the same results in these versions the short example should
be <literal>mt_rand (5, 11)</literal> to get a random number
between 5 and 15.
</para>
</note>
<simpara>
See also:
<function>mt_srand</function>,
<function>mt_getrandmax</function>, and
<function>rand</function>.
</simpara>
</refsect1>
</refentry>
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