mirror of
https://github.com/sigmasternchen/php-doc-en
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75 lines
2.2 KiB
XML
75 lines
2.2 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<book xml:id="book.bc" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
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<?phpdoc extension-membership="bundled" ?>
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<title>BCMath Arbitrary Precision Mathematics</title>
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<titleabbrev>BC Math</titleabbrev>
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<!-- {{{ preface -->
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<preface xml:id="intro.bc">
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&reftitle.intro;
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<para>
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For arbitrary precision mathematics PHP offers BCMath which
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supports numbers of any size and precision up to <literal>2147483647</literal> (or <literal>0x7FFFFFFF</literal>) decimal digits,
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if there is sufficient memory, represented as strings.
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</para>
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<para>
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Valid (aka. well-formed) BCMath numbers are strings which match the regular expression
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<literal>/^[+-]?[0-9]*(\.[0-9]*)?$/</literal>.
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</para>
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<caution>
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<para>
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Passing values of type <type>float</type> to a BCMath function which expects
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a <type>string</type> as operand may not have the desired effect due to the
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way PHP converts <type>float</type> values to <type>string</type>, namely
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that the <type>string</type> may be in exponential notation (which is not
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supported by BCMath), and that, prior to PHP 8.0.0, the decimal separator is locale dependent
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(while BCMath always expects a decimal point).
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</para>
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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$num1 = 0; // (string) 0 => '0'
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$num2 = -0.000005; // (string) -0.000005 => '-5.05E-6'
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echo bcadd($num1, $num2, 6); // => '0.000000'
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setlocale(LC_NUMERIC, 'de_DE'); // uses a decimal comma
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$num2 = 1.2; // (string) 1.2 => '1,2'
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echo bcsub($num1, $num2, 1); // => '0.0'
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?>
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]]>
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</programlisting>
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</informalexample>
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</caution>
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</preface>
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<!-- }}} -->
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&reference.bc.setup;
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&reference.bc.constants;
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&reference.bc.reference;
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</book>
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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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