doc/ref/Reference/size.html

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<html><head><title>boost::mpl::size</title>
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<h1><a href="../Table_of_Contents.html"><img src="../mpl_logo.jpg" alt="[Home]" border=0 align="right"></a>size</h1><h3>Synopsis</h3>
<p>
<pre>
template&lt;
      typename Sequence
    &gt;
struct size
{
    typedef <em>unspecified</em> type;
};
</pre>
<p>
<h3>Description</h3>
<p>
<code>size</code> returns the number of elements in the sequence, that is, the number of elements in the range <code>[begin&lt;Sequence&gt;::type,end&lt;Sequence&gt;::type)</code>.
<p>
<h3>Definition</h3>
<p>
<pre>
#include "<a href="../../../../../boost/mpl/size.hpp">boost/mpl/size.hpp</a>"
</pre>
<p>
<h3>Parameters</h3>
<table border="1">
<tr><th>&nbsp;Parameter&nbsp;</th><th>&nbsp;Requirement&nbsp;</th><th>&nbsp;Description &nbsp;</th></tr>
<tr><td><code>Sequence</code></td><td>A model of <a href="../Sequence.html">Sequence</a></td><td></td></tr>
</table>
<p>
<h3>Expression semantics</h3>
<p>
<table border="1">
<tr><th>&nbsp;Expression&nbsp;</th><th>&nbsp;Expression&nbsp;type&nbsp;</th><th>&nbsp;Precondition&nbsp;</th><th>&nbsp;Semantics&nbsp;</th><th>&nbsp;Postcondition&nbsp;</th></tr>
<tr><td><code>typedef size&lt;Sequence&gt;::type s;</code></td><td>A model of <a href="../Integral_Constant.html">Integral Constant</a></td><td></td><td>Equivalent to <code>typedef distance&lt; begin&lt;Sequence&gt;::type,end&lt;Sequence&gt;::type &gt;::type s;</code></td><td><code>s::value &gt;= 0</code> </td></tr>
</table>
<p>
<h3>Complexity</h3>
<p>
The complexity of the <code>size</code> algorithm directly depends on the implementation of the particular sequence it is applied to. In the worst case <code>size</code> has a linear complexity. As a general rule, if the <code>Sequence</code> is a <a href="../Random_Access_Sequence.html">Random Access Sequence</a>, you can be certain that <code>size&lt;Sequence&gt;::type</code> is an amortized constant time operation. The opposite is not necessary true - for example, a model of <a href="../Forward_Sequence.html">Forward Sequence</a> still can guarantee you an amortized constant time <code>size</code> complexity. Please refer the documentation page of the concrete sequence type for further information. 
<p>
<h3>Example</h3>
<p>
<pre>
typedef list0&lt;&gt; empty_list;
typedef vector_c&lt;int,0,1,2,3,4,5&gt; numbers;
typedef range_c&lt;int,0,100&gt; more_numbers;
<p>
BOOST_STATIC_ASSERT(size&lt;list&gt;::type::value == 0);
BOOST_STATIC_ASSERT(size&lt;numbers&gt;::type::value == 5);
BOOST_STATIC_ASSERT(size&lt;more_numbers&gt;::type::value == 100);
</pre>
<p>
<h3>See also</h3>
<p>
<a href="../Sequence.html">Sequence</a>, <code><a href="../Reference/empty.html">empty</a></code>, <code><a href="../Reference/begin.html">begin</a></code>, <code><a href="../Reference/end.html">end</a></code>
<p><hr>
<a href="../Table_of_Contents.html">Table of Contents</a><br>Last edited July 17, 2002 3:51 am</body></html>
Added libs/mpl 2002-09-16 19:25:33 +00:00			`<!doctype html public "-//ietf//dtd html//en">`
update the docs 2003-03-12 13:29:12 +00:00			`<html><head><title>boost::mpl::size</title>`
Added libs/mpl 2002-09-16 19:25:33 +00:00			`<link rel="stylesheet" href="../mpl_wiki.css">`
			`</head><body bgcolor="white">`
update the docs 2003-03-12 13:29:12 +00:00			`<h1><a href="../Table_of_Contents.html"><img src="../mpl_logo.jpg" alt="[Home]" border=0 align="right"></a>size</h1><h3>Synopsis</h3>`
Added libs/mpl 2002-09-16 19:25:33 +00:00			`<p>`
			`<pre>`
			`template<`
			`typename Sequence`
			`>`
			`struct size`
			`{`
			`typedef <em>unspecified</em> type;`
			`};`
			`</pre>`
			`<p>`
			`<h3>Description</h3>`
			`<p>`
			`<code>size</code> returns the number of elements in the sequence, that is, the number of elements in the range <code>[begin<Sequence>::type,end<Sequence>::type)</code>.`
			`<p>`
			`<h3>Definition</h3>`
			`<p>`
			`<pre>`
update the docs 2003-03-12 13:29:12 +00:00			`#include "<a href="../../../../../boost/mpl/size.hpp">boost/mpl/size.hpp</a>"`
Added libs/mpl 2002-09-16 19:25:33 +00:00			`</pre>`
			`<p>`
			`<h3>Parameters</h3>`
			`<table border="1">`
			`<tr><th> Parameter </th><th> Requirement </th><th> Description  </th></tr>`
			`<tr><td><code>Sequence</code></td><td>A model of <a href="../Sequence.html">Sequence</a></td><td></td></tr>`
			`</table>`
			`<p>`
			`<h3>Expression semantics</h3>`
			`<p>`
			`<table border="1">`
			`<tr><th> Expression </th><th> Expression type </th><th> Precondition </th><th> Semantics </th><th> Postcondition </th></tr>`
			`<tr><td><code>typedef size<Sequence>::type s;</code></td><td>A model of <a href="../Integral_Constant.html">Integral Constant</a></td><td></td><td>Equivalent to <code>typedef distance< begin<Sequence>::type,end<Sequence>::type >::type s;</code></td><td><code>s::value >= 0</code> </td></tr>`
			`</table>`
			`<p>`
			`<h3>Complexity</h3>`
			`<p>`
			The complexity of the <code>size</code> algorithm directly depends on the implementation of the particular sequence it is applied to. In the worst case <code>size</code> has a linear complexity. As a general rule, if the <code>Sequence</code> is a <a href="../Random_Access_Sequence.html">Random Access Sequence</a>, you can be certain that <code>size<Sequence>::type</code> is an amortized constant time operation. The opposite is not necessary true - for example, a model of <a href="../Forward_Sequence.html">Forward Sequence</a> still can guarantee you an amortized constant time <code>size</code> complexity. Please refer the documentation page of the concrete sequence type for further information.
			`<p>`
			`<h3>Example</h3>`
			`<p>`
			`<pre>`
			`typedef list0<> empty_list;`
			`typedef vector_c<int,0,1,2,3,4,5> numbers;`
			`typedef range_c<int,0,100> more_numbers;`
			`<p>`
			`BOOST_STATIC_ASSERT(size<list>::type::value == 0);`
			`BOOST_STATIC_ASSERT(size<numbers>::type::value == 5);`
			`BOOST_STATIC_ASSERT(size<more_numbers>::type::value == 100);`
			`</pre>`
			`<p>`
			`<h3>See also</h3>`
			`<p>`
			`<a href="../Sequence.html">Sequence</a>, <code><a href="../Reference/empty.html">empty</a></code>, <code><a href="../Reference/begin.html">begin</a></code>, <code><a href="../Reference/end.html">end</a></code>`
			`<p><hr>`
update the docs 2003-03-12 13:29:12 +00:00			`<a href="../Table_of_Contents.html">Table of Contents</a><br>Last edited July 17, 2002 3:51 am</body></html>`