1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Tutorial: view_interface</title> 6<link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../stl_interfaces.html" title="Chapter 38. Boost.STLInterfaces"> 10<link rel="prev" href="tutorial___iterator_interface_.html" title="Tutorial: iterator_interface"> 11<link rel="next" href="tutorial___sequence_container_interface_.html" title="Tutorial: sequence_container_interface"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> 16<td align="center"><a href="../../../index.html">Home</a></td> 17<td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> 18<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 19<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 20<td align="center"><a href="../../../more/index.htm">More</a></td> 21</tr></table> 22<hr> 23<div class="spirit-nav"> 24<a accesskey="p" href="tutorial___iterator_interface_.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../stl_interfaces.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="tutorial___sequence_container_interface_.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="section"> 27<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 28<a name="boost_stlinterfaces.tutorial___view_interface_"></a><a class="link" href="tutorial___view_interface_.html" title="Tutorial: view_interface">Tutorial: 29 <code class="computeroutput"><span class="identifier">view_interface</span></code></a> 30</h2></div></div></div> 31<div class="note"><table border="0" summary="Note"> 32<tr> 33<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../doc/src/images/note.png"></td> 34<th align="left">Note</th> 35</tr> 36<tr><td align="left" valign="top"><p> 37 All the member functions provided by <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code> are in your 38 view's base class — <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code> — and 39 can therefore be hidden if you define a member function with the same name 40 in your derived view. If you don't like the semantics of any <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code>-provided member 41 function, feel free to replace it. 42 </p></td></tr> 43</table></div> 44<h4> 45<a name="boost_stlinterfaces.tutorial___view_interface_.h0"></a> 46 <span class="phrase"><a name="boost_stlinterfaces.tutorial___view_interface_.the__code__phrase_role__identifier__view_interface__phrase___code__template"></a></span><a class="link" href="tutorial___view_interface_.html#boost_stlinterfaces.tutorial___view_interface_.the__code__phrase_role__identifier__view_interface__phrase___code__template">The 47 <code class="computeroutput"><span class="identifier">view_interface</span></code> Template</a> 48 </h4> 49<p> 50 C++20 contains a <a href="https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern" target="_top">CRTP</a> 51 template, <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ranges</span><span class="special">::</span><span class="identifier">view_interface</span></code>, which takes a range or view, 52 and adds all the operations that view types have, using only the range's/view's 53 <code class="computeroutput"><span class="identifier">begin</span><span class="special">()</span></code> 54 and <code class="computeroutput"><span class="identifier">end</span><span class="special">()</span></code>. 55 This is a C++14-compatible version of that template. 56 </p> 57<p> 58 As with <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/iterator_interface.html" title="Struct template iterator_interface">iterator_interface</a></code>, <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code> 59 makes it possible to write very few operations — only <code class="computeroutput"><span class="identifier">begin</span><span class="special">()</span></code> and 60 <code class="computeroutput"><span class="identifier">end</span><span class="special">()</span></code> 61 are actually used by <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code> — and get 62 all the other operations that go with view types. The operations added depend 63 on what kinds of iterator and/or sentinel types your derived view type defines. 64 </p> 65<p> 66 Here is the declaration of <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code>: 67 </p> 68<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Derived</span><span class="special">,</span> <span class="identifier">element_layout</span> <span class="identifier">Contiguity</span> <span class="special">=</span> <span class="identifier">element_layout</span><span class="special">::</span><span class="identifier">discontiguous</span><span class="special">></span> 69<span class="keyword">struct</span> <span class="identifier">view_interface</span><span class="special">;</span> 70</pre> 71<p> 72 <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code> 73 only requires the derived type and an optional non-type template parameter 74 that indicates whether <code class="computeroutput"><span class="identifier">Derived</span></code>'s 75 iterators are contiguous. The non-type parameter is necessary to support pre-C++20 76 code. 77 </p> 78<div class="note"><table border="0" summary="Note"> 79<tr> 80<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../doc/src/images/note.png"></td> 81<th align="left">Note</th> 82</tr> 83<tr><td align="left" valign="top"><p> 84 Proxy iterators are inherently discontiguous. 85 </p></td></tr> 86</table></div> 87<p> 88 In this example, we're implementing something very similar to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ranges</span><span class="special">::</span><span class="identifier">drop_while_view</span></code>. 89 First, we need helper view types <code class="computeroutput"><span class="identifier">subrange</span></code> 90 and <code class="computeroutput"><span class="identifier">all_view</span></code>, and a function 91 that takes a range and returns a view of the entire range, <code class="computeroutput"><span class="identifier">all</span><span class="special">()</span></code>: 92 </p> 93<p> 94</p> 95<pre class="programlisting"><span class="comment">// A subrange is simply an iterator-sentinel pair. This one is a bit simpler</span> 96<span class="comment">// than the one in std::ranges; its missing a bunch of constructors, prev(),</span> 97<span class="comment">// next(), and advance().</span> 98<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Iterator</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Sentinel</span><span class="special">></span> 99<span class="keyword">struct</span> <span class="identifier">subrange</span> 100 <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">stl_interfaces</span><span class="special">::</span><span class="identifier">view_interface</span><span class="special"><</span><span class="identifier">subrange</span><span class="special"><</span><span class="identifier">Iterator</span><span class="special">,</span> <span class="identifier">Sentinel</span><span class="special">>></span> 101<span class="special">{</span> 102 <span class="identifier">subrange</span><span class="special">()</span> <span class="special">=</span> <span class="keyword">default</span><span class="special">;</span> 103 <span class="keyword">constexpr</span> <span class="identifier">subrange</span><span class="special">(</span><span class="identifier">Iterator</span> <span class="identifier">it</span><span class="special">,</span> <span class="identifier">Sentinel</span> <span class="identifier">s</span><span class="special">)</span> <span class="special">:</span> <span class="identifier">first_</span><span class="special">(</span><span class="identifier">it</span><span class="special">),</span> <span class="identifier">last_</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span> <span class="special">{}</span> 104 105 <span class="keyword">constexpr</span> <span class="keyword">auto</span> <span class="identifier">begin</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">first_</span><span class="special">;</span> <span class="special">}</span> 106 <span class="keyword">constexpr</span> <span class="keyword">auto</span> <span class="identifier">end</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">last_</span><span class="special">;</span> <span class="special">}</span> 107 108<span class="keyword">private</span><span class="special">:</span> 109 <span class="identifier">Iterator</span> <span class="identifier">first_</span><span class="special">;</span> 110 <span class="identifier">Sentinel</span> <span class="identifier">last_</span><span class="special">;</span> 111<span class="special">};</span> 112 113<span class="comment">// std::view::all() returns one of several types, depending on what you pass</span> 114<span class="comment">// it. Here, we're keeping it simple; all() always returns a subrange.</span> 115<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Range</span><span class="special">></span> 116<span class="keyword">auto</span> <span class="identifier">all</span><span class="special">(</span><span class="identifier">Range</span> <span class="special">&&</span> <span class="identifier">range</span><span class="special">)</span> 117<span class="special">{</span> 118 <span class="keyword">return</span> <span class="identifier">subrange</span><span class="special"><</span><span class="keyword">decltype</span><span class="special">(</span><span class="identifier">range</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()),</span> <span class="keyword">decltype</span><span class="special">(</span><span class="identifier">range</span><span class="special">.</span><span class="identifier">end</span><span class="special">())>(</span> 119 <span class="identifier">range</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">range</span><span class="special">.</span><span class="identifier">end</span><span class="special">());</span> 120<span class="special">}</span> 121 122<span class="comment">// A template alias that denotes the type of all(r) for some Range r.</span> 123<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Range</span><span class="special">></span> 124<span class="keyword">using</span> <span class="identifier">all_view</span> <span class="special">=</span> <span class="keyword">decltype</span><span class="special">(</span><span class="identifier">all</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">declval</span><span class="special"><</span><span class="identifier">Range</span><span class="special">>()));</span> 125</pre> 126<p> 127 </p> 128<p> 129 Note that <code class="computeroutput"><span class="identifier">subrange</span></code> is derived 130 from <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code>, so it will have 131 all the view-like operations that are appropriate to its <code class="computeroutput"><span class="identifier">Iterator</span></code> 132 and <code class="computeroutput"><span class="identifier">Sentinel</span></code> types. 133 </p> 134<p> 135 With the helpers available, we can define <code class="computeroutput"><span class="identifier">drop_while_view</span></code>: 136 </p> 137<p> 138</p> 139<pre class="programlisting"><span class="comment">// Perhaps its clear now why we defined subrange, all(), etc. above.</span> 140<span class="comment">// drop_while_view contains a view data member. If we just took any old range</span> 141<span class="comment">// that was passed to drop_while_view's constructor, we'd copy the range</span> 142<span class="comment">// itself, which may be a std::vector. So, we want to make a view out of</span> 143<span class="comment">// whatever Range we're given so that this copy of an owning range does not</span> 144<span class="comment">// happen.</span> 145<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Range</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Pred</span><span class="special">></span> 146<span class="keyword">struct</span> <span class="identifier">drop_while_view</span> 147 <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">stl_interfaces</span><span class="special">::</span><span class="identifier">view_interface</span><span class="special"><</span><span class="identifier">drop_while_view</span><span class="special"><</span><span class="identifier">Range</span><span class="special">,</span> <span class="identifier">Pred</span><span class="special">>></span> 148<span class="special">{</span> 149 <span class="keyword">using</span> <span class="identifier">base_type</span> <span class="special">=</span> <span class="identifier">all_view</span><span class="special"><</span><span class="identifier">Range</span><span class="special">>;</span> 150 151 <span class="identifier">drop_while_view</span><span class="special">()</span> <span class="special">=</span> <span class="keyword">default</span><span class="special">;</span> 152 153 <span class="keyword">constexpr</span> <span class="identifier">drop_while_view</span><span class="special">(</span><span class="identifier">Range</span> <span class="special">&</span> <span class="identifier">base</span><span class="special">,</span> <span class="identifier">Pred</span> <span class="identifier">pred</span><span class="special">)</span> <span class="special">:</span> 154 <span class="identifier">base_</span><span class="special">(</span><span class="identifier">all</span><span class="special">(</span><span class="identifier">base</span><span class="special">)),</span> 155 <span class="identifier">pred_</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">pred</span><span class="special">))</span> 156 <span class="special">{}</span> 157 158 <span class="keyword">constexpr</span> <span class="identifier">base_type</span> <span class="identifier">base</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">base_</span><span class="special">;</span> <span class="special">}</span> 159 <span class="keyword">constexpr</span> <span class="identifier">Pred</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">pred</span><span class="special">()</span> <span class="keyword">const</span> <span class="keyword">noexcept</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">pred_</span><span class="special">;</span> <span class="special">}</span> 160 161 <span class="comment">// A more robust implementation should probably cache the value computed</span> 162 <span class="comment">// by this function, so that subsequent calls can just return the cached</span> 163 <span class="comment">// iterator.</span> 164 <span class="keyword">constexpr</span> <span class="keyword">auto</span> <span class="identifier">begin</span><span class="special">()</span> 165 <span class="special">{</span> 166 <span class="comment">// We're forced to write this out as a raw loop, since no</span> 167 <span class="comment">// std::-namespace algorithms accept a sentinel.</span> 168 <span class="keyword">auto</span> <span class="identifier">first</span> <span class="special">=</span> <span class="identifier">base_</span><span class="special">.</span><span class="identifier">begin</span><span class="special">();</span> 169 <span class="keyword">auto</span> <span class="keyword">const</span> <span class="identifier">last</span> <span class="special">=</span> <span class="identifier">base_</span><span class="special">.</span><span class="identifier">end</span><span class="special">();</span> 170 <span class="keyword">for</span> <span class="special">(;</span> <span class="identifier">first</span> <span class="special">!=</span> <span class="identifier">last</span><span class="special">;</span> <span class="special">++</span><span class="identifier">first</span><span class="special">)</span> <span class="special">{</span> 171 <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">pred_</span><span class="special">(*</span><span class="identifier">first</span><span class="special">))</span> 172 <span class="keyword">break</span><span class="special">;</span> 173 <span class="special">}</span> 174 <span class="keyword">return</span> <span class="identifier">first</span><span class="special">;</span> 175 <span class="special">}</span> 176 177 <span class="keyword">constexpr</span> <span class="keyword">auto</span> <span class="identifier">end</span><span class="special">()</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">base_</span><span class="special">.</span><span class="identifier">end</span><span class="special">();</span> <span class="special">}</span> 178 179<span class="keyword">private</span><span class="special">:</span> 180 <span class="identifier">base_type</span> <span class="identifier">base_</span><span class="special">;</span> 181 <span class="identifier">Pred</span> <span class="identifier">pred_</span><span class="special">;</span> 182<span class="special">};</span> 183 184<span class="comment">// Since this is a C++14 and later library, we're not using CTAD; we therefore</span> 185<span class="comment">// need a make-function.</span> 186<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Range</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Pred</span><span class="special">></span> 187<span class="keyword">auto</span> <span class="identifier">make_drop_while_view</span><span class="special">(</span><span class="identifier">Range</span> <span class="special">&</span> <span class="identifier">base</span><span class="special">,</span> <span class="identifier">Pred</span> <span class="identifier">pred</span><span class="special">)</span> 188<span class="special">{</span> 189 <span class="keyword">return</span> <span class="identifier">drop_while_view</span><span class="special"><</span><span class="identifier">Range</span><span class="special">,</span> <span class="identifier">Pred</span><span class="special">>(</span><span class="identifier">base</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">pred</span><span class="special">));</span> 190<span class="special">}</span> 191</pre> 192<p> 193 </p> 194<p> 195 Now, let's look at code using these types, including operations defined by 196 <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code> 197 that we did not have to write: 198 </p> 199<p> 200</p> 201<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="keyword">const</span> <span class="identifier">ints</span> <span class="special">=</span> <span class="special">{</span><span class="number">2</span><span class="special">,</span> <span class="number">4</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="number">4</span><span class="special">,</span> <span class="number">5</span><span class="special">,</span> <span class="number">6</span><span class="special">};</span> 202 203<span class="comment">// all() returns a subrange, which is a view type containing ints.begin()</span> 204<span class="comment">// and ints.end().</span> 205<span class="keyword">auto</span> <span class="identifier">all_ints</span> <span class="special">=</span> <span class="identifier">all</span><span class="special">(</span><span class="identifier">ints</span><span class="special">);</span> 206 207<span class="comment">// This works using just the used-defined members of subrange: begin() and</span> 208<span class="comment">// end().</span> 209<span class="identifier">assert</span><span class="special">(</span> 210 <span class="identifier">std</span><span class="special">::</span><span class="identifier">equal</span><span class="special">(</span><span class="identifier">all_ints</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">all_ints</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> <span class="identifier">ints</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">ints</span><span class="special">.</span><span class="identifier">end</span><span class="special">()));</span> 211 212<span class="comment">// These are available because subrange is derived from view_interface.</span> 213<span class="identifier">assert</span><span class="special">(</span><span class="identifier">all_ints</span><span class="special">[</span><span class="number">2</span><span class="special">]</span> <span class="special">==</span> <span class="number">3</span><span class="special">);</span> 214<span class="identifier">assert</span><span class="special">(</span><span class="identifier">all_ints</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span> <span class="special">==</span> <span class="number">6u</span><span class="special">);</span> 215 216<span class="keyword">auto</span> <span class="identifier">even</span> <span class="special">=</span> <span class="special">[](</span><span class="keyword">int</span> <span class="identifier">x</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">x</span> <span class="special">%</span> <span class="number">2</span> <span class="special">==</span> <span class="number">0</span><span class="special">;</span> <span class="special">};</span> 217<span class="keyword">auto</span> <span class="identifier">ints_after_even_prefix</span> <span class="special">=</span> <span class="identifier">make_drop_while_view</span><span class="special">(</span><span class="identifier">ints</span><span class="special">,</span> <span class="identifier">even</span><span class="special">);</span> 218 219<span class="comment">// Available via begin()/end()...</span> 220<span class="identifier">assert</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">equal</span><span class="special">(</span> 221 <span class="identifier">ints_after_even_prefix</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> 222 <span class="identifier">ints_after_even_prefix</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> 223 <span class="identifier">ints</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()</span> <span class="special">+</span> <span class="number">2</span><span class="special">,</span> 224 <span class="identifier">ints</span><span class="special">.</span><span class="identifier">end</span><span class="special">()));</span> 225 226<span class="comment">// ... and via view_interface.</span> 227<span class="identifier">assert</span><span class="special">(!</span><span class="identifier">ints_after_even_prefix</span><span class="special">.</span><span class="identifier">empty</span><span class="special">());</span> 228<span class="identifier">assert</span><span class="special">(</span><span class="identifier">ints_after_even_prefix</span><span class="special">[</span><span class="number">2</span><span class="special">]</span> <span class="special">==</span> <span class="number">5</span><span class="special">);</span> 229<span class="identifier">assert</span><span class="special">(</span><span class="identifier">ints_after_even_prefix</span><span class="special">.</span><span class="identifier">back</span><span class="special">()</span> <span class="special">==</span> <span class="number">6</span><span class="special">);</span> 230</pre> 231<p> 232 </p> 233<p> 234 If you want more details on <code class="computeroutput"><a class="link" href="../boost/stl_interfaces/v1/view_interface.html" title="Struct template view_interface">view_interface</a></code>, you can find 235 it wherever you usually find reference documentation on the standard library. 236 We won't cover it here for that reason. See <a href="http://eel.is/c++draft/view.interface" target="_top">[view.interface</a> 237 on eel.is] or <a href="https://cppreference.com" target="_top">https://cppreference.com</a> 238 for details. 239 </p> 240</div> 241<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 242<td align="left"></td> 243<td align="right"><div class="copyright-footer">Copyright © 2019 T. Zachary Laine<p> 244 Distributed under the Boost Software License, Version 1.0. (See accompanying 245 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>) 246 </p> 247</div></td> 248</tr></table> 249<hr> 250<div class="spirit-nav"> 251<a accesskey="p" href="tutorial___iterator_interface_.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../stl_interfaces.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="tutorial___sequence_container_interface_.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 252</div> 253</body> 254</html> 255
