mirror of
https://github.com/sigmasternchen/php-doc-en
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git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@339019 c90b9560-bf6c-de11-be94-00142212c4b1
261 lines
7.7 KiB
XML
261 lines
7.7 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<refentry xml:id="function.round" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>round</refname>
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<refpurpose>Rounds a float</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>float</type><methodname>round</methodname>
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<methodparam><type>float</type><parameter>val</parameter></methodparam>
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<methodparam choice="opt"><type>int</type><parameter>precision</parameter><initializer>0</initializer></methodparam>
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<methodparam choice="opt"><type>int</type><parameter>mode</parameter><initializer>PHP_ROUND_HALF_UP</initializer></methodparam>
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</methodsynopsis>
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<para>
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Returns the rounded value of <parameter>val</parameter> to
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specified <parameter>precision</parameter>
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(number of digits after the decimal point).
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<parameter>precision</parameter> can also be negative or zero (default).
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</para>
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<!-- It's not true
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<para>
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<caution>
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<simpara>
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When rounding on exact halves <function>round</function> rounds down on
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evens and up on odds. If you want to always force it in one direction
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on a .5 (or .05 in your case) add or subtract a tiny fuzz factor. The
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reason behind rounding half the values down and the other half up is to
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avoid the classical banking problem where if you always rounded down
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you would be stealing money from your customers, or if you always
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rounded up you would end up over time losing money. By averaging it
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out through evens and odds you statistically break even.
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</simpara>
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</caution>
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</para>
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-->
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<para>
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<note>
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<simpara>
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PHP doesn't handle strings like <literal>"12,300.2"</literal> correctly
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by default. See <link linkend="language.types.string.conversion"
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>converting from strings</link>.
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</simpara>
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</note>
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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<varlistentry>
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<term><parameter>val</parameter></term>
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<listitem>
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<para>
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The value to round
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>precision</parameter></term>
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<listitem>
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<para>
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The optional number of decimal digits to round to.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>mode</parameter></term>
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<listitem>
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<para>
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Use one of the following constants to specify the mode in which rounding occurs.
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<informaltable>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>Constant</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><constant>PHP_ROUND_HALF_UP</constant></entry>
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<entry>
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Round <parameter>val</parameter> up to <parameter>precision</parameter> decimal places
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away from zero, when it is half way there. Making 1.5 into 2 and -1.5 into -2.
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</entry>
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</row>
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<row>
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<entry><constant>PHP_ROUND_HALF_DOWN</constant></entry>
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<entry>
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Round <parameter>val</parameter> down to <parameter>precision</parameter> decimal places
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towards zero, when it is half way there. Making 1.5 into 1 and -1.5 into -1.
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</entry>
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</row>
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<row>
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<entry><constant>PHP_ROUND_HALF_EVEN</constant></entry>
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<entry>
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Round <parameter>val</parameter> to <parameter>precision</parameter> decimal places
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towards the next even value.
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</entry>
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</row>
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<row>
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<entry><constant>PHP_ROUND_HALF_ODD</constant></entry>
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<entry>
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Round <parameter>val</parameter> to <parameter>precision</parameter> decimal places
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towards the next odd value.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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The rounded value
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</para>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<example>
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<title><function>round</function> examples</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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echo round(3.4); // 3
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echo round(3.5); // 4
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echo round(3.6); // 4
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echo round(3.6, 0); // 4
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echo round(1.95583, 2); // 1.96
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echo round(1241757, -3); // 1242000
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echo round(5.045, 2); // 5.05
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echo round(5.055, 2); // 5.06
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?>
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]]>
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</programlisting>
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</example>
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</para>
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<para>
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<example>
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<title><parameter>mode</parameter> examples</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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echo round(9.5, 0, PHP_ROUND_HALF_UP); // 10
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echo round(9.5, 0, PHP_ROUND_HALF_DOWN); // 9
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echo round(9.5, 0, PHP_ROUND_HALF_EVEN); // 10
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echo round(9.5, 0, PHP_ROUND_HALF_ODD); // 9
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echo round(8.5, 0, PHP_ROUND_HALF_UP); // 9
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echo round(8.5, 0, PHP_ROUND_HALF_DOWN); // 8
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echo round(8.5, 0, PHP_ROUND_HALF_EVEN); // 8
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echo round(8.5, 0, PHP_ROUND_HALF_ODD); // 9
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?>
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]]>
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</programlisting>
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</example>
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<example>
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<title><parameter>mode</parameter> with precision examples</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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/* Using PHP_ROUND_HALF_UP with 1 decimal digit precision */
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echo round( 1.55, 1, PHP_ROUND_HALF_UP); // 1.6
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echo round( 1.54, 1, PHP_ROUND_HALF_UP); // 1.5
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echo round(-1.55, 1, PHP_ROUND_HALF_UP); // -1.6
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echo round(-1.54, 1, PHP_ROUND_HALF_UP); // -1.5
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/* Using PHP_ROUND_HALF_DOWN with 1 decimal digit precision */
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echo round( 1.55, 1, PHP_ROUND_HALF_DOWN); // 1.5
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echo round( 1.54, 1, PHP_ROUND_HALF_DOWN); // 1.5
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echo round(-1.55, 1, PHP_ROUND_HALF_DOWN); // -1.5
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echo round(-1.54, 1, PHP_ROUND_HALF_DOWN); // -1.5
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/* Using PHP_ROUND_HALF_EVEN with 1 decimal digit precision */
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echo round( 1.55, 1, PHP_ROUND_HALF_EVEN); // 1.6
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echo round( 1.54, 1, PHP_ROUND_HALF_EVEN); // 1.5
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echo round(-1.55, 1, PHP_ROUND_HALF_EVEN); // -1.6
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echo round(-1.54, 1, PHP_ROUND_HALF_EVEN); // -1.5
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/* Using PHP_ROUND_HALF_ODD with 1 decimal digit precision */
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echo round( 1.55, 1, PHP_ROUND_HALF_ODD); // 1.5
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echo round( 1.54, 1, PHP_ROUND_HALF_ODD); // 1.5
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echo round(-1.55, 1, PHP_ROUND_HALF_ODD); // -1.5
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echo round(-1.54, 1, PHP_ROUND_HALF_ODD); // -1.5
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?>
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]]>
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</programlisting>
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</example>
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</para>
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</refsect1>
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<refsect1 role="changelog">
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&reftitle.changelog;
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<para>
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<informaltable>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>&Version;</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>5.3.0</entry>
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<entry>
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The <parameter>mode</parameter> parameter was introduced.
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</entry>
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</row>
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<row>
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<entry>5.2.7</entry>
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<entry>
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The inner workings of <function>round</function> was changed
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to conform to the C99 standard.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</para>
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</refsect1>
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<refsect1 role="seealso">
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&reftitle.seealso;
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<para>
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<simplelist>
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<member><function>ceil</function></member>
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<member><function>floor</function></member>
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<member><function>number_format</function></member>
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</simplelist>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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