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<h1 class="title">Introduction</h1>
<p class="para">
For arbitrary precision mathematics PHP offers the Binary Calculator which
supports numbers of any size and precision up to <em>2147483647</em> (or <em>0x7FFFFFFF</em>) decimals,
if there is sufficient memory, represented as strings.
</p>
<div class="caution"><strong class="caution">Caution</strong>
<p class="para">
Passing values of type <span class="type"><a href="language.types.float.html" class="type float">float</a></span> to a BCMath function which expects
a <span class="type"><a href="language.types.string.html" class="type string">string</a></span> as operand may not have the desired effect due to the
way PHP converts <span class="type"><a href="language.types.float.html" class="type float">float</a></span> values to <span class="type"><a href="language.types.string.html" class="type string">string</a></span>, namely
that the <span class="type"><a href="language.types.string.html" class="type string">string</a></span> may be in exponential notation (what is not
supported by BCMath), and that the decimal separator is locale dependend
(while BCMath always expects a decimal point).
</p>
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$num1 </span><span style="color: #007700">= </span><span style="color: #0000BB">0</span><span style="color: #007700">; </span><span style="color: #FF8000">// (string) 0 => '0'<br /></span><span style="color: #0000BB">$num2 </span><span style="color: #007700">= -</span><span style="color: #0000BB">0.000005</span><span style="color: #007700">; </span><span style="color: #FF8000">// (string) -0.000005 => '-5.05E-6'<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">bcadd</span><span style="color: #007700">(</span><span style="color: #0000BB">$num1</span><span style="color: #007700">, </span><span style="color: #0000BB">$num2</span><span style="color: #007700">, </span><span style="color: #0000BB">6</span><span style="color: #007700">); </span><span style="color: #FF8000">// => '0.000000'<br /><br /></span><span style="color: #0000BB">setlocale</span><span style="color: #007700">(</span><span style="color: #0000BB">LC_NUMERIC</span><span style="color: #007700">, </span><span style="color: #DD0000">'de_DE'</span><span style="color: #007700">); </span><span style="color: #FF8000">// uses a decimal comma<br /></span><span style="color: #0000BB">$num2 </span><span style="color: #007700">= </span><span style="color: #0000BB">1.2</span><span style="color: #007700">; </span><span style="color: #FF8000">// (string) 1.2 => '1,2'<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">bcsub</span><span style="color: #007700">(</span><span style="color: #0000BB">$num1</span><span style="color: #007700">, </span><span style="color: #0000BB">$num2</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">); </span><span style="color: #FF8000">// => '0.0'<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
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