1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Useful functions</title> 5<link rel="stylesheet" href="../../boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../index.html" title="Chapter 1. Boost.Bimap"> 8<link rel="up" href="../the_tutorial.html" title="The tutorial"> 9<link rel="prev" href="differences_with_standard_maps.html" title="Differences with standard maps"> 10<link rel="next" href="bimaps_with_user_defined_names.html" title="Bimaps with user defined names"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="differences_with_standard_maps.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../the_tutorial.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="bimaps_with_user_defined_names.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h3 class="title"> 27<a name="boost_bimap.the_tutorial.useful_functions"></a><a class="link" href="useful_functions.html" title="Useful functions">Useful functions</a> 28</h3></div></div></div> 29<div class="toc"><dl class="toc"> 30<dt><span class="section"><a href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.projection_of_iterators">Projection 31 of iterators</a></span></dt> 32<dt><span class="section"><a href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.replace_and_modify">replace 33 and modify</a></span></dt> 34<dt><span class="section"><a href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges">Retrieval 35 of ranges</a></span></dt> 36</dl></div> 37<div class="section"> 38<div class="titlepage"><div><div><h4 class="title"> 39<a name="boost_bimap.the_tutorial.useful_functions.projection_of_iterators"></a><a class="link" href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.projection_of_iterators" title="Projection of iterators">Projection 40 of iterators</a> 41</h4></div></div></div> 42<p> 43 Iterators can be projected to any of the three views of the bimap. A bimap 44 provides three member functions to cope with projection: <code class="computeroutput"><span class="identifier">project_left</span></code>, <code class="computeroutput"><span class="identifier">project_right</span></code> 45 and <code class="computeroutput"><span class="identifier">project_up</span></code>, with projects 46 iterators to the <span class="emphasis"><em>left map view</em></span>, the <span class="emphasis"><em>right 47 map view</em></span> and the <span class="emphasis"><em>collection of relations view</em></span>. 48 These functions take any iterator from the bimap and retrieve an iterator 49 over the projected view pointing to the same element. 50 </p> 51<p> 52 Here is an example that uses projection: 53 </p> 54<p> 55 <a href="../../../../example/projection.cpp" target="_top">Go to source code</a> 56 </p> 57<p> 58</p> 59<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">bimap</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">,</span><span class="identifier">multiset_of</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">greater</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="special">></span> <span class="special">></span> <span class="identifier">bm_type</span><span class="special">;</span> 60 61<span class="identifier">bm_type</span> <span class="identifier">bm</span><span class="special">;</span> 62<span class="identifier">bm</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">(</span><span class="string">"John"</span> <span class="special">,</span><span class="number">34</span><span class="special">)</span> <span class="special">);</span> 63<span class="identifier">bm</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">(</span><span class="string">"Peter"</span><span class="special">,</span><span class="number">24</span><span class="special">)</span> <span class="special">);</span> 64<span class="identifier">bm</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">(</span><span class="string">"Mary"</span> <span class="special">,</span><span class="number">12</span><span class="special">)</span> <span class="special">);</span> 65 66<span class="comment">// Find the name of the next younger person after Peter</span> 67 68<span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_const_iterator</span> <span class="identifier">name_iter</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">find</span><span class="special">(</span><span class="string">"Peter"</span><span class="special">);</span> 69 70<span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">right_const_iterator</span> <span class="identifier">years_iter</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">project_right</span><span class="special">(</span><span class="identifier">name_iter</span><span class="special">);</span> 71 72<span class="special">++</span><span class="identifier">years_iter</span><span class="special">;</span> 73 74<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"The next younger person after Peter is "</span> <span class="special"><<</span> <span class="identifier">years_iter</span><span class="special">-></span><span class="identifier">second</span><span class="special">;</span> 75</pre> 76<p> 77 </p> 78</div> 79<div class="section"> 80<div class="titlepage"><div><div><h4 class="title"> 81<a name="boost_bimap.the_tutorial.useful_functions.replace_and_modify"></a><a class="link" href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.replace_and_modify" title="replace and modify">replace 82 and modify</a> 83</h4></div></div></div> 84<p> 85 These functions are members of the views of a bimap that are not founded 86 in their standard counterparts. 87 </p> 88<p> 89 The <code class="computeroutput"><span class="identifier">replace</span></code> family member 90 functions performs in-place replacement of a given element as the following 91 example shows: 92 </p> 93<p> 94 <a href="../../../../example/tutorial_modify_and_replace.cpp" target="_top">Go to source 95 code</a> 96 </p> 97<p> 98</p> 99<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">bimap</span><span class="special"><</span> <span class="keyword">int</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">></span> <span class="identifier">bm_type</span><span class="special">;</span> 100<span class="identifier">bm_type</span> <span class="identifier">bm</span><span class="special">;</span> 101 102<span class="identifier">bm</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="string">"one"</span><span class="special">)</span> <span class="special">);</span> 103 104<span class="comment">// Replace (1,"one") with (1,"1") using the right map view</span> 105<span class="special">{</span> 106 <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">right_iterator</span> <span class="identifier">it</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span><span class="special">.</span><span class="identifier">find</span><span class="special">(</span><span class="string">"one"</span><span class="special">);</span> 107 108 <span class="keyword">bool</span> <span class="identifier">successful_replace</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span><span class="special">.</span><span class="identifier">replace_key</span><span class="special">(</span> <span class="identifier">it</span><span class="special">,</span> <span class="string">"1"</span> <span class="special">);</span> 109 110 <span class="identifier">assert</span><span class="special">(</span> <span class="identifier">successful_replace</span> <span class="special">);</span> 111<span class="special">}</span> 112 113<span class="identifier">bm</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">(</span><span class="number">2</span><span class="special">,</span><span class="string">"two"</span><span class="special">)</span> <span class="special">);</span> 114 115<span class="comment">// Fail to replace (1,"1") with (1,"two") using the left map view</span> 116<span class="special">{</span> 117 <span class="identifier">assert</span><span class="special">(</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span> <span class="special">==</span> <span class="number">2</span> <span class="special">);</span> 118 119 <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_iterator</span> <span class="identifier">it</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">find</span><span class="special">(</span><span class="number">1</span><span class="special">);</span> 120 121 <span class="keyword">bool</span> <span class="identifier">successful_replace</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">replace_data</span><span class="special">(</span> <span class="identifier">it</span><span class="special">,</span> <span class="string">"two"</span> <span class="special">);</span> 122 123 <a class="co" name="boost_bimap.the_tutorial.useful_functions.replace_and_modify.c0" href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.replace_and_modify.c1"><img src="../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a><span class="identifier">assert</span><span class="special">(</span> <span class="special">!</span> <span class="identifier">successful_replace</span> <span class="special">);</span> 124 <span class="identifier">assert</span><span class="special">(</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span> <span class="special">==</span> <span class="number">2</span> <span class="special">);</span> 125<span class="special">}</span> 126</pre> 127<p> 128 </p> 129<div class="calloutlist"><table border="0" summary="Callout list"><tr> 130<td width="5%" valign="top" align="left"><p><a name="boost_bimap.the_tutorial.useful_functions.replace_and_modify.c1"></a><a href="#boost_bimap.the_tutorial.useful_functions.replace_and_modify.c0"><img src="../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a> </p></td> 131<td valign="top" align="left"><p> 132 <code class="computeroutput"><span class="identifier">it</span></code> is still valid here, 133 and the bimap was left unchanged 134 </p></td> 135</tr></table></div> 136<p> 137 <code class="computeroutput"><span class="identifier">replace</span></code> functions performs 138 this substitution in such a manner that: 139 </p> 140<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 141<li class="listitem"> 142 The complexity is constant time if the changed element retains its 143 original order with respect to all views; it is logarithmic otherwise. 144 </li> 145<li class="listitem"> 146 Iterator and reference validity are preserved. 147 </li> 148<li class="listitem"> 149 The operation is strongly exception-safe, i.e. the <code class="computeroutput"><span class="identifier">bimap</span></code> 150 remains unchanged if some exception (originated by the system or the 151 user's data types) is thrown. 152 </li> 153</ul></div> 154<p> 155 <code class="computeroutput"><span class="identifier">replace</span></code> functions are powerful 156 operations not provided by standard STL containers, and one that is specially 157 handy when strong exception-safety is required. 158 </p> 159<p> 160 The observant reader might have noticed that the convenience of replace 161 comes at a cost: namely the whole element has to be copied <span class="emphasis"><em>twice</em></span> 162 to do the updating (when retrieving it and inside <code class="computeroutput"><span class="identifier">replace</span></code>). 163 If elements are expensive to copy, this may be quite a computational cost 164 for the modification of just a tiny part of the object. To cope with this 165 situation, Boost.Bimap provides an alternative updating mechanism: <code class="computeroutput"><span class="identifier">modify</span></code> functions. 166 </p> 167<p> 168 <code class="computeroutput"><span class="identifier">modify</span></code> functions accepts 169 a functor (or pointer to function) taking a reference to the data to be 170 changed, thus eliminating the need for spurious copies. Like <code class="computeroutput"><span class="identifier">replace</span></code> functions, <code class="computeroutput"><span class="identifier">modify</span></code> 171 functions does preserve the internal orderings of all the indices of the 172 <code class="computeroutput"><span class="identifier">bimap</span></code>. However, the semantics 173 of modify functions are not entirely equivalent to replace functions. Consider 174 what happens if a collision occurs as a result of modifying the element, 175 i.e. the modified element clashes with another with respect to some unique 176 view. In the case of <code class="computeroutput"><span class="identifier">replace</span></code> 177 functions, the original value is kept and the method returns without altering 178 the container, but <code class="computeroutput"><span class="identifier">modify</span></code> 179 functions cannot afford such an approach, since the modifying functor leaves 180 no trace of the previous value of the element. Integrity constraints thus 181 lead to the following policy: when a collision happens in the process of 182 calling a modify functions, the element is erased and the method returns 183 false. This difference in behavior between <code class="computeroutput"><span class="identifier">replace</span></code> 184 and <code class="computeroutput"><span class="identifier">modify</span></code> functions has 185 to be considered by the programmer on a case-by-case basis. 186 </p> 187<p> 188 Boost.Bimap defines new placeholders named <code class="computeroutput"><span class="identifier">_key</span></code> 189 and <code class="computeroutput"><span class="identifier">_data</span></code> to allow a sounder 190 solution. You have to include <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">bimap</span><span class="special">/</span><span class="identifier">support</span><span class="special">/</span><span class="identifier">lambda</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 191 to use them. 192 </p> 193<p> 194 <a href="../../../../example/tutorial_modify_and_replace.cpp" target="_top">Go to source 195 code</a> 196 </p> 197<p> 198</p> 199<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">bimap</span><span class="special"><</span> <span class="keyword">int</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">></span> <span class="identifier">bm_type</span><span class="special">;</span> 200<span class="identifier">bm_type</span> <span class="identifier">bm</span><span class="special">;</span> 201<span class="identifier">bm</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="string">"one"</span><span class="special">)</span> <span class="special">);</span> 202 203<span class="comment">// Modify (1,"one") to (1,"1") using the right map view</span> 204<span class="special">{</span> 205 <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">right_iterator</span> <span class="identifier">it</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span><span class="special">.</span><span class="identifier">find</span><span class="special">(</span><span class="string">"one"</span><span class="special">);</span> 206 207 <span class="keyword">bool</span> <span class="identifier">successful_modify</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span><span class="special">.</span><span class="identifier">modify_key</span><span class="special">(</span> <span class="identifier">it</span> <span class="special">,</span> <span class="identifier">_key</span> <span class="special">=</span> <span class="string">"1"</span> <span class="special">);</span> 208 209 <span class="identifier">assert</span><span class="special">(</span> <span class="identifier">successful_modify</span> <span class="special">);</span> 210<span class="special">}</span> 211 212<span class="identifier">bm</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">(</span><span class="number">2</span><span class="special">,</span><span class="string">"two"</span><span class="special">)</span> <span class="special">);</span> 213 214<span class="comment">// Fail to modify (1,"1") to (1,"two") using the left map view</span> 215<span class="special">{</span> 216 <span class="identifier">assert</span><span class="special">(</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span> <span class="special">==</span> <span class="number">2</span> <span class="special">);</span> 217 218 <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_iterator</span> <span class="identifier">it</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">find</span><span class="special">(</span><span class="number">1</span><span class="special">);</span> 219 220 <span class="keyword">bool</span> <span class="identifier">successful_modify</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">modify_data</span><span class="special">(</span> <span class="identifier">it</span><span class="special">,</span> <span class="identifier">_data</span> <span class="special">=</span> <span class="string">"two"</span> <span class="special">);</span> 221 222 <a class="co" name="boost_bimap.the_tutorial.useful_functions.replace_and_modify.c2" href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.replace_and_modify.c3"><img src="../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a><span class="identifier">assert</span><span class="special">(</span> <span class="special">!</span> <span class="identifier">successful_modify</span> <span class="special">);</span> 223 <span class="identifier">assert</span><span class="special">(</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span> <span class="special">==</span> <span class="number">1</span> <span class="special">);</span> 224<span class="special">}</span> 225</pre> 226<p> 227 </p> 228<div class="calloutlist"><table border="0" summary="Callout list"><tr> 229<td width="5%" valign="top" align="left"><p><a name="boost_bimap.the_tutorial.useful_functions.replace_and_modify.c3"></a><a href="#boost_bimap.the_tutorial.useful_functions.replace_and_modify.c2"><img src="../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a> </p></td> 230<td valign="top" align="left"><p> 231 <code class="computeroutput"><span class="identifier">it</span></code> is not longer valid 232 and <code class="computeroutput"><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="string">"1"</span><span class="special">)</span></code> is removed from the bimap 233 </p></td> 234</tr></table></div> 235</div> 236<div class="section"> 237<div class="titlepage"><div><div><h4 class="title"> 238<a name="boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges"></a><a class="link" href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges" title="Retrieval of ranges">Retrieval 239 of ranges</a> 240</h4></div></div></div> 241<p> 242 Standard <code class="computeroutput"><span class="identifier">lower_bound</span></code> and 243 <code class="computeroutput"><span class="identifier">upper_bound</span></code> functions can 244 be used to lookup for all the elements in a given range. 245 </p> 246<p> 247 Suppose we want to retrieve the elements from a <code class="computeroutput"><span class="identifier">bimap</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">></span></code> where the left value is in the range 248 <code class="computeroutput"><span class="special">[</span><span class="number">20</span><span class="special">,</span><span class="number">50</span><span class="special">]</span></code> 249 </p> 250<p> 251</p> 252<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">bimap</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">></span> <span class="identifier">bm_type</span><span class="special">;</span> 253<span class="identifier">bm_type</span> <span class="identifier">bm</span><span class="special">;</span> 254 255<span class="comment">// ...</span> 256 257<span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_iterator</span> <span class="identifier">iter_first</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">lower_bound</span><span class="special">(</span><span class="number">20</span><span class="special">);</span> 258<span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_iterator</span> <span class="identifier">iter_second</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">upper_bound</span><span class="special">(</span><span class="number">50</span><span class="special">);</span> 259 260<span class="comment">// range [iter_first,iter_second) contains the elements in [20,50]</span> 261</pre> 262<p> 263 </p> 264<p> 265 Subtle changes to the code are required when strict inequalities are considered. 266 To retrieve the elements greater than 20 and less than 50, the code has 267 to be rewritten as 268 </p> 269<p> 270</p> 271<pre class="programlisting"><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_iterator</span> <span class="identifier">iter_first</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">upper_bound</span><span class="special">(</span><span class="number">20</span><span class="special">);</span> 272<span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_iterator</span> <span class="identifier">iter_second</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">lower_bound</span><span class="special">(</span><span class="number">50</span><span class="special">);</span> 273 274<span class="comment">// range [iter_first,iter_second) contains the elements in (20,50)</span> 275</pre> 276<p> 277 </p> 278<p> 279 To add to this complexity, the careful programmer has to take into account 280 that the lower and upper bounds of the interval searched be compatible: 281 for instance, if the lower bound is 50 and the upper bound is 20, the iterators 282 <code class="computeroutput"><span class="identifier">iter_first</span></code> and <code class="computeroutput"><span class="identifier">iter_second</span></code> produced by the code above 283 will be in reverse order, with possibly catastrophic results if a traversal 284 from <code class="computeroutput"><span class="identifier">iter_first</span></code> to <code class="computeroutput"><span class="identifier">iter_second</span></code> is tried. All these details 285 make range searching a tedious and error prone task. 286 </p> 287<p> 288 The range member function, often in combination with lambda expressions, 289 can greatly help alleviate this situation: 290 </p> 291<p> 292</p> 293<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">bimap</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">></span> <span class="identifier">bm_type</span><span class="special">;</span> 294<span class="identifier">bm_type</span> <span class="identifier">bm</span><span class="special">;</span> 295 296<span class="comment">// ...</span> 297 298<a class="co" name="boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c0" href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c1"><img src="../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_range_type</span> <span class="identifier">r</span><span class="special">;</span> 299 300<a class="co" name="boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c2" href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c3"><img src="../../../../../../doc/src/images/callouts/2.png" alt="2" border="0"></a><span class="identifier">r</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">range</span><span class="special">(</span> <span class="number">20</span> <span class="special"><=</span> <span class="identifier">_key</span><span class="special">,</span> <span class="identifier">_key</span> <span class="special"><=</span> <span class="number">50</span> <span class="special">);</span> <span class="comment">// [20,50]</span> 301 302<span class="identifier">r</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">range</span><span class="special">(</span> <span class="number">20</span> <span class="special"><</span> <span class="identifier">_key</span><span class="special">,</span> <span class="identifier">_key</span> <span class="special"><</span> <span class="number">50</span> <span class="special">);</span> <span class="comment">// (20,50)</span> 303 304<span class="identifier">r</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">range</span><span class="special">(</span> <span class="number">20</span> <span class="special"><=</span> <span class="identifier">_key</span><span class="special">,</span> <span class="identifier">_key</span> <span class="special"><</span> <span class="number">50</span> <span class="special">);</span> <span class="comment">// [20,50)</span> 305</pre> 306<p> 307 </p> 308<div class="calloutlist"><table border="0" summary="Callout list"> 309<tr> 310<td width="5%" valign="top" align="left"><p><a name="boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c1"></a><a href="#boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c0"><img src="../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a> </p></td> 311<td valign="top" align="left"><p> 312 <code class="computeroutput"><span class="identifier">range_type</span></code> is a handy 313 typedef equal to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="identifier">iterator</span><span class="special">,</span><span class="identifier">iterator</span><span class="special">></span></code>. <code class="computeroutput"><span class="identifier">const_range_type</span></code> 314 is provided too, and it is equal to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="identifier">const_iterator</span><span class="special">,</span><span class="identifier">const_iterator</span><span class="special">></span></code> 315 </p></td> 316</tr> 317<tr> 318<td width="5%" valign="top" align="left"><p><a name="boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c3"></a><a href="#boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c2"><img src="../../../../../../doc/src/images/callouts/2.png" alt="2" border="0"></a> </p></td> 319<td valign="top" align="left"><p> 320 _key is a Boost.Lambda placeholder. To use it you have to include 321 <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">bimap</span><span class="special">/</span><span class="identifier">support</span><span class="special">/</span><span class="identifier">lambda</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 322 </p></td> 323</tr> 324</table></div> 325<p> 326 <code class="computeroutput"><span class="identifier">range</span></code> simply accepts predicates 327 specifying the lower and upper bounds of the interval searched. Please 328 consult the reference for a detailed explanation of the permissible predicates 329 passed to range. 330 </p> 331<p> 332 One or both bounds can be omitted with the special unbounded marker: 333 </p> 334<p> 335</p> 336<pre class="programlisting"><span class="identifier">r</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">range</span><span class="special">(</span> <span class="number">20</span> <span class="special"><=</span> <span class="identifier">_key</span><span class="special">,</span> <span class="identifier">unbounded</span> <span class="special">);</span> <span class="comment">// [20,inf)</span> 337 338<span class="identifier">r</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">range</span><span class="special">(</span> <span class="identifier">unbounded</span> <span class="special">,</span> <span class="identifier">_key</span> <span class="special"><</span> <span class="number">50</span> <span class="special">);</span> <span class="comment">// (-inf,50)</span> 339 340<a class="co" name="boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c4" href="useful_functions.html#boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c5"><img src="../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a><span class="identifier">r</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span><span class="special">.</span><span class="identifier">range</span><span class="special">(</span> <span class="identifier">unbounded</span> <span class="special">,</span> <span class="identifier">unbounded</span> <span class="special">);</span> <span class="comment">// (-inf,inf)</span> 341</pre> 342<p> 343 </p> 344<div class="calloutlist"><table border="0" summary="Callout list"><tr> 345<td width="5%" valign="top" align="left"><p><a name="boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c5"></a><a href="#boost_bimap.the_tutorial.useful_functions.retrieval_of_ranges.c4"><img src="../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a> </p></td> 346<td valign="top" align="left"><p> 347 This is equivalent to std::make_pair(s.begin(),s.end()) 348 </p></td> 349</tr></table></div> 350<p> 351 <a href="../../../../example/tutorial_range.cpp" target="_top">Go to source code</a> 352 </p> 353</div> 354</div> 355<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 356<td align="left"></td> 357<td align="right"><div class="copyright-footer">Copyright © 2006-2012 Matias Capeletto<p> 358 Distributed under the Boost Software License, Version 1.0. (See accompanying 359 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>) 360 </p> 361</div></td> 362</tr></table> 363<hr> 364<div class="spirit-nav"> 365<a accesskey="p" href="differences_with_standard_maps.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../the_tutorial.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="bimaps_with_user_defined_names.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 366</div> 367</body> 368</html> 369
