Google Git
Sign in
nest-open-source / nest-cam / 4320010 / boost / 62d1066a6d52d5ac4e10c106f0eab14c820be0ce / . / boost / libs / range / doc / html / range / reference / adaptors / reference / indexed.html
blob: 6b068c2d8af5cbd328ce03e175c79c4c194cfb83 [file] [log] [blame]
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>indexed</title>
<link rel="stylesheet" href="../../../../../../../../doc/src/boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
<link rel="home" href="../../../../index.html" title="Chapter&#160;1.&#160;Range 2.0">
<link rel="up" href="../reference.html" title="Reference">
<link rel="prev" href="filtered.html" title="filtered">
<link rel="next" href="indirected.html" title="indirected">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr>
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../../boost.png"></td>
<td align="center"><a href="../../../../../../../../index.html">Home</a></td>
<td align="center"><a href="../../../../../../../../libs/libraries.htm">Libraries</a></td>
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
<td align="center"><a href="../../../../../../../../more/index.htm">More</a></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="filtered.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="indirected.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="range.reference.adaptors.reference.indexed"></a><a class="link" href="indexed.html" title="indexed">indexed</a>
</h5></div></div></div>
<div class="toc"><dl class="toc"><dt><span class="section"><a href="indexed.html#range.reference.adaptors.reference.indexed.indexed_example">indexed
example</a></span></dt></dl></div>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
<p>
Syntax
</p>
</th>
<th>
<p>
Code
</p>
</th>
</tr></thead>
<tbody>
<tr>
<td>
<p>
Pipe
</p>
</td>
<td>
<p>
<code class="computeroutput"><span class="identifier">rng</span> <span class="special">|</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">indexed</span><span class="special">()</span></code>
</p>
</td>
</tr>
<tr>
<td>
<p>
Pipe
</p>
</td>
<td>
<p>
<code class="computeroutput"><span class="identifier">rng</span> <span class="special">|</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">indexed</span><span class="special">(</span><span class="identifier">start_index</span><span class="special">)</span></code>
</p>
</td>
</tr>
<tr>
<td>
<p>
Function
</p>
</td>
<td>
<p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">index</span><span class="special">(</span><span class="identifier">rng</span><span class="special">)</span></code>
</p>
</td>
</tr>
<tr>
<td>
<p>
Function
</p>
</td>
<td>
<p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">index</span><span class="special">(</span><span class="identifier">rng</span><span class="special">,</span>
<span class="identifier">start_index</span><span class="special">)</span></code>
</p>
</td>
</tr>
</tbody>
</table></div>
<h6>
<a name="range.reference.adaptors.reference.indexed.h0"></a>
<span class="phrase"><a name="range.reference.adaptors.reference.indexed.description"></a></span><a class="link" href="indexed.html#range.reference.adaptors.reference.indexed.description">Description</a>
</h6>
<p>
The index within each returned <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range</span><span class="special">::</span><span class="identifier">index_value</span></code>
is equal to <code class="computeroutput"><span class="identifier">start_index</span></code>
+ the offset of the element from the beginning of the range. In the versions
of the functions that omit <code class="computeroutput"><span class="identifier">start_index</span></code>
the starting index is taken to be <code class="computeroutput"><span class="number">0</span></code>.
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Purpose:</strong></span> Adapt <code class="computeroutput"><span class="identifier">rng</span></code>
to return elements that have the corresponding value from <code class="computeroutput"><span class="identifier">rng</span></code> and a numeric index.
</li>
<li class="listitem">
<span class="bold"><strong>Returns:</strong></span> A range adapted to return
both the element and the associated index. The returned range has
elements of type:
</li>
</ul></div>
<p>
</p>
<pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range</span><span class="special">::</span><span class="identifier">index_value</span><span class="special">&lt;</span>
<span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reference</span><span class="special">&lt;</span><span class="keyword">decltype</span><span class="special">(</span><span class="identifier">rng</span><span class="special">)&gt;::</span><span class="identifier">type</span><span class="special">,</span>
<span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_difference</span><span class="special">&lt;</span><span class="keyword">decltype</span><span class="special">(</span><span class="identifier">rng</span><span class="special">)&gt;::</span><span class="identifier">type</span>
<span class="special">&gt;</span>
</pre>
<p>
</p>
<p>
The synopsis of index_value is as follows:
</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Indexable</span><span class="special">=</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">ptrdiff_t</span><span class="special">&gt;</span>
<span class="keyword">class</span> <span class="identifier">index_value</span> <span class="special">:</span> <span class="keyword">public</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">tuple</span><span class="special">&lt;</span><span class="identifier">Indexable</span><span class="special">,</span> <span class="identifier">T</span><span class="special">&gt;</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="keyword">typedef</span> <span class="special">...</span><span class="identifier">unspecified</span><span class="special">...</span> <span class="identifier">index_type</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="special">...</span><span class="identifier">unspecified</span><span class="special">...</span> <span class="identifier">const_index_type</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="special">...</span><span class="identifier">unspecified</span><span class="special">...</span> <span class="identifier">value_type</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="special">...</span><span class="identifier">unspecified</span><span class="special">...</span> <span class="identifier">const_value_type</span><span class="special">;</span>
<span class="comment">// ...unspecified... constructors</span>
<span class="identifier">index_type</span> <span class="identifier">index</span><span class="special">();</span>
<span class="identifier">const_index_type</span> <span class="identifier">index</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="identifier">value_type</span> <span class="identifier">value</span><span class="special">();</span>
<span class="identifier">const_value_type</span> <span class="identifier">value</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<span class="bold"><strong>Range Category:</strong></span> <a class="link" href="../../../concepts/single_pass_range.html" title="Single Pass Range">Single
Pass Range</a>
</li>
<li class="listitem">
<span class="bold"><strong>Range Return Type:</strong></span> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">indexed_range</span><span class="special">&lt;</span><span class="keyword">decltype</span><span class="special">(</span><span class="identifier">rng</span><span class="special">)&gt;</span></code>
</li>
<li class="listitem">
<span class="bold"><strong>Returned Range Category:</strong></span> The range
category of <code class="computeroutput"><span class="identifier">rng</span></code> if
and only if <code class="computeroutput"><span class="identifier">rng</span></code> is
not a <a class="link" href="../../../concepts/bidirectional_range.html" title="Bidirectional Range">Bidirectional
Range</a>. If <code class="computeroutput"><span class="identifier">rng</span></code>
is a <a class="link" href="../../../concepts/bidirectional_range.html" title="Bidirectional Range">Bidirectional
Range</a> then the returned range category is <a class="link" href="../../../concepts/forward_range.html" title="Forward Range">Forward
Range</a>. The rationale for the demotion of <a class="link" href="../../../concepts/bidirectional_range.html" title="Bidirectional Range">Bidirectional
Range</a> inputs to <a class="link" href="../../../concepts/forward_range.html" title="Forward Range">Forward
Range</a> is to avoid slow calculation of indices for <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">rng</span><span class="special">)</span></code>.
</li>
</ul></div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="range.reference.adaptors.reference.indexed.indexed_example"></a><a class="link" href="indexed.html#range.reference.adaptors.reference.indexed.indexed_example" title="indexed example">indexed
example</a>
</h6></div></div></div>
<p>
</p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">range</span><span class="special">/</span><span class="identifier">adaptor</span><span class="special">/</span><span class="identifier">indexed</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">assign</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iterator</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">vector</span><span class="special">&gt;</span>
<span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">argc</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">argv</span><span class="special">[])</span>
<span class="special">{</span>
<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">assign</span><span class="special">;</span>
<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">input</span><span class="special">;</span>
<span class="identifier">input</span> <span class="special">+=</span> <span class="number">10</span><span class="special">,</span><span class="number">20</span><span class="special">,</span><span class="number">30</span><span class="special">,</span><span class="number">40</span><span class="special">,</span><span class="number">50</span><span class="special">,</span><span class="number">60</span><span class="special">,</span><span class="number">70</span><span class="special">,</span><span class="number">80</span><span class="special">,</span><span class="number">90</span><span class="special">;</span>
<span class="keyword">for</span> <span class="special">(</span><span class="keyword">const</span> <span class="keyword">auto</span><span class="special">&amp;</span> <span class="identifier">element</span> <span class="special">:</span> <span class="identifier">input</span> <span class="special">|</span> <span class="identifier">indexed</span><span class="special">(</span><span class="number">0</span><span class="special">))</span>
<span class="special">{</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"Element = "</span> <span class="special">&lt;&lt;</span> <span class="identifier">element</span><span class="special">.</span><span class="identifier">value</span><span class="special">()</span>
<span class="special">&lt;&lt;</span> <span class="string">" Index = "</span> <span class="special">&lt;&lt;</span> <span class="identifier">element</span><span class="special">.</span><span class="identifier">index</span><span class="special">()</span>
<span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="special">}</span>
<span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
</p>
</div>
<p>
This would produce the output:
</p>
<pre class="programlisting"><span class="identifier">Element</span> <span class="special">=</span> <span class="number">10</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">0</span>
<span class="identifier">Element</span> <span class="special">=</span> <span class="number">20</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">1</span>
<span class="identifier">Element</span> <span class="special">=</span> <span class="number">30</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">2</span>
<span class="identifier">Element</span> <span class="special">=</span> <span class="number">40</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">3</span>
<span class="identifier">Element</span> <span class="special">=</span> <span class="number">50</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">4</span>
<span class="identifier">Element</span> <span class="special">=</span> <span class="number">60</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">5</span>
<span class="identifier">Element</span> <span class="special">=</span> <span class="number">70</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">6</span>
<span class="identifier">Element</span> <span class="special">=</span> <span class="number">80</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">7</span>
<span class="identifier">Element</span> <span class="special">=</span> <span class="number">90</span> <span class="identifier">Index</span> <span class="special">=</span> <span class="number">8</span>
</pre>
<p>
</p>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2010 Thorsten Ottosen,
Neil Groves<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
</p>
</div></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="filtered.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="indirected.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
</body>
</html>