]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | <html> |
2 | <head> | |
3 | <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> | |
4 | <title>One minute tutorial</title> | |
5 | <link rel="stylesheet" href="../boostbook.css" type="text/css"> | |
6 | <meta name="generator" content="DocBook XSL Stylesheets V1.77.1"> | |
7 | <link rel="home" href="../index.html" title="Chapter 1. Boost.Bimap"> | |
8 | <link rel="up" href="../index.html" title="Chapter 1. Boost.Bimap"> | |
9 | <link rel="prev" href="introduction.html" title="Introduction"> | |
10 | <link rel="next" href="the_tutorial.html" title="The tutorial"> | |
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="introduction.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="the_tutorial.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> | |
24 | </div> | |
25 | <div class="section boost_bimap_one_minute_tutorial"> | |
26 | <div class="titlepage"><div><div><h2 class="title" style="clear: both"> | |
27 | <a name="boost_bimap.one_minute_tutorial"></a><a class="link" href="one_minute_tutorial.html" title="One minute tutorial">One minute tutorial</a> | |
28 | </h2></div></div></div> | |
29 | <h4> | |
30 | <a name="boost_bimap.one_minute_tutorial.h0"></a> | |
31 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.what_is_a_bimap_"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.what_is_a_bimap_">What | |
32 | is a bimap?</a> | |
33 | </h4> | |
34 | <p> | |
35 | A Bimap is a data structure that represents bidirectional relations between | |
36 | elements of two collections. The container is designed to work as two opposed | |
37 | STL maps. A bimap between a collection <code class="computeroutput"><span class="identifier">X</span></code> | |
38 | and a collection <code class="computeroutput"><span class="identifier">Y</span></code> can be viewed | |
39 | as a map from <code class="computeroutput"><span class="identifier">X</span></code> to <code class="computeroutput"><span class="identifier">Y</span></code> (this view will be called the <span class="emphasis"><em>left | |
40 | map view</em></span>) or as a map from <code class="computeroutput"><span class="identifier">Y</span></code> | |
41 | to <code class="computeroutput"><span class="identifier">X</span></code> (known as the <span class="emphasis"><em>right | |
42 | map view</em></span>). Additionally, the bimap can also be viewed as a set of | |
43 | relations between <code class="computeroutput"><span class="identifier">X</span></code> and <code class="computeroutput"><span class="identifier">Y</span></code> (named the <span class="emphasis"><em>collection of relations | |
44 | view</em></span>). | |
45 | </p> | |
46 | <p> | |
47 | The following code creates an empty bimap container: | |
48 | </p> | |
49 | <pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">bimap</span><span class="special"><</span><span class="identifier">X</span><span class="special">,</span><span class="identifier">Y</span><span class="special">></span> <span class="identifier">bm_type</span><span class="special">;</span> | |
50 | <span class="identifier">bm_type</span> <span class="identifier">bm</span><span class="special">;</span> | |
51 | </pre> | |
52 | <p> | |
53 | Given this code, the following is the complete description of the resulting | |
54 | bimap. <a href="#ftn.boost_bimap.one_minute_tutorial.f0" class="footnote"><sup class="footnote"><a name="boost_bimap.one_minute_tutorial.f0"></a>[1]</sup></a> | |
55 | </p> | |
56 | <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> | |
57 | <li class="listitem"> | |
58 | <code class="computeroutput"><span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span></code> is signature-compatible with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="identifier">X</span><span class="special">,</span><span class="identifier">Y</span><span class="special">></span></code> | |
59 | </li> | |
60 | <li class="listitem"> | |
61 | <code class="computeroutput"><span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span></code> is signature-compatible with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="identifier">Y</span><span class="special">,</span><span class="identifier">X</span><span class="special">></span></code> | |
62 | </li> | |
63 | <li class="listitem"> | |
64 | <code class="computeroutput"><span class="identifier">bm</span></code> is signature-compatible | |
65 | with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span><span class="special"><</span> <span class="identifier">relation</span><span class="special"><</span><span class="identifier">X</span><span class="special">,</span><span class="identifier">Y</span><span class="special">></span> <span class="special">></span></code> | |
66 | </li> | |
67 | </ul></div> | |
68 | <p> | |
69 | <span class="inlinemediaobject"><img src="../images/bimap/simple.bimap.png" alt="simple.bimap"></span> | |
70 | </p> | |
71 | <p> | |
72 | You can see how a bimap container offers three views over the same collection | |
73 | of bidirectional relations. | |
74 | </p> | |
75 | <p> | |
76 | If we have any generic function that work with maps | |
77 | </p> | |
78 | <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">class</span> <span class="identifier">MapType</span> <span class="special">></span> | |
79 | <span class="keyword">void</span> <span class="identifier">print_map</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">MapType</span> <span class="special">&</span> <span class="identifier">m</span><span class="special">)</span> | |
80 | <span class="special">{</span> | |
81 | <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">MapType</span><span class="special">::</span><span class="identifier">const_iterator</span> <span class="identifier">const_iterator</span><span class="special">;</span> | |
82 | <span class="keyword">for</span><span class="special">(</span> <span class="identifier">const_iterator</span> <span class="identifier">iter</span> <span class="special">=</span> <span class="identifier">m</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">iend</span> <span class="special">=</span> <span class="identifier">m</span><span class="special">.</span><span class="identifier">end</span><span class="special">();</span> <span class="identifier">iter</span> <span class="special">!=</span> <span class="identifier">iend</span><span class="special">;</span> <span class="special">++</span><span class="identifier">iter</span> <span class="special">)</span> | |
83 | <span class="special">{</span> | |
84 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">iter</span><span class="special">-></span><span class="identifier">first</span> <span class="special"><<</span> <span class="string">"-->"</span> <span class="special"><<</span> <span class="identifier">iter</span><span class="special">-></span><span class="identifier">second</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
85 | <span class="special">}</span> | |
86 | <span class="special">}</span> | |
87 | </pre> | |
88 | <p> | |
89 | We can use the <span class="emphasis"><em>left map view</em></span> and the <span class="emphasis"><em>right map | |
90 | view</em></span> with it | |
91 | </p> | |
92 | <pre class="programlisting"><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</span><span class="special">;</span> | |
93 | <span class="special">...</span> | |
94 | <span class="identifier">print_map</span><span class="special">(</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span> <span class="special">);</span> | |
95 | <span class="identifier">print_map</span><span class="special">(</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span> <span class="special">);</span> | |
96 | </pre> | |
97 | <p> | |
98 | And the output will be | |
99 | </p> | |
100 | <pre class="programlisting"><code class="literal">1 --> one</code> | |
101 | <code class="literal">2 --> two</code> | |
102 | ... | |
103 | <code class="literal">one --> 1</code> | |
104 | <code class="literal">two --> 2</code> | |
105 | ... | |
106 | </pre> | |
107 | <h4> | |
108 | <a name="boost_bimap.one_minute_tutorial.h1"></a> | |
109 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.layout_of_the_relation_and_the_pairs_of_a_bimap"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.layout_of_the_relation_and_the_pairs_of_a_bimap">Layout | |
110 | of the relation and the pairs of a bimap</a> | |
111 | </h4> | |
112 | <p> | |
113 | The <code class="computeroutput"><span class="identifier">relation</span></code> class represents | |
114 | two related elements. The two values are named left and right to express the | |
115 | symmetry of this type. The bimap pair classes are signature-compatible with | |
116 | <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pairs</span></code>. | |
117 | </p> | |
118 | <p> | |
119 | <span class="inlinemediaobject"><img src="../images/bimap/relation.and.pair.png" alt="relation.and.pair"></span> | |
120 | </p> | |
121 | <h4> | |
122 | <a name="boost_bimap.one_minute_tutorial.h2"></a> | |
123 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.step_by_step"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.step_by_step">Step | |
124 | by step</a> | |
125 | </h4> | |
126 | <p> | |
127 | A convenience header is available in the boost directory: | |
128 | </p> | |
129 | <pre class="programlisting"><span class="preprocessor">#include</span> <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">hpp</span><span class="special">></span> | |
130 | </pre> | |
131 | <p> | |
132 | Lets define a bidirectional map between integers and strings: | |
133 | </p> | |
134 | <p> | |
135 | </p> | |
136 | <pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</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> | |
137 | <span class="identifier">bm_type</span> <span class="identifier">bm</span><span class="special">;</span> | |
138 | </pre> | |
139 | <p> | |
140 | </p> | |
141 | <h4> | |
142 | <a name="boost_bimap.one_minute_tutorial.h3"></a> | |
143 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.the_collection_of_relations_view"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.the_collection_of_relations_view">The | |
144 | collection of relations view</a> | |
145 | </h4> | |
146 | <p> | |
147 | Remember that <code class="computeroutput"><span class="identifier">bm</span></code> alone can | |
148 | be used as a set of relations. We can insert elements or iterate over them | |
149 | using this view. | |
150 | </p> | |
151 | <p> | |
152 | </p> | |
153 | <pre class="programlisting"><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> | |
154 | <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> | |
155 | ||
156 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"There are "</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="string">"relations"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
157 | ||
158 | <span class="keyword">for</span><span class="special">(</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">const_iterator</span> <span class="identifier">iter</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">iend</span> <span class="special">=</span> <span class="identifier">bm</span><span class="special">.</span><span class="identifier">end</span><span class="special">();</span> | |
159 | <span class="identifier">iter</span> <span class="special">!=</span> <span class="identifier">iend</span><span class="special">;</span> <span class="special">++</span><span class="identifier">iter</span> <span class="special">)</span> | |
160 | <span class="special">{</span> | |
161 | <span class="comment">// iter->left : data : int</span> | |
162 | <span class="comment">// iter->right : data : std::string</span> | |
163 | ||
164 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">iter</span><span class="special">-></span><span class="identifier">left</span> <span class="special"><<</span> <span class="string">" <--> "</span> <span class="special"><<</span> <span class="identifier">iter</span><span class="special">-></span><span class="identifier">right</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
165 | <span class="special">}</span> | |
166 | </pre> | |
167 | <p> | |
168 | </p> | |
169 | <h4> | |
170 | <a name="boost_bimap.one_minute_tutorial.h4"></a> | |
171 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.the_left_map_view"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.the_left_map_view">The | |
172 | left map view</a> | |
173 | </h4> | |
174 | <p> | |
175 | <code class="computeroutput"><span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span></code> works like a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span> | |
176 | <span class="keyword">int</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> | |
177 | <span class="special">></span></code>. We use it in the same way we will | |
178 | use a standard map. | |
179 | </p> | |
180 | <p> | |
181 | </p> | |
182 | <pre class="programlisting"><a class="co" name="boost_bimap.one_minute_tutorial.c0" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.c1"><img src="../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a><span class="keyword">typedef</span> <span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_map</span><span class="special">::</span><span class="identifier">const_iterator</span> <span class="identifier">left_const_iterator</span><span class="special">;</span> | |
183 | ||
184 | <span class="keyword">for</span><span class="special">(</span> <span class="identifier">left_const_iterator</span> <span class="identifier">left_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">begin</span><span class="special">(),</span> <span class="identifier">iend</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">end</span><span class="special">();</span> | |
185 | <span class="identifier">left_iter</span> <span class="special">!=</span> <span class="identifier">iend</span><span class="special">;</span> <span class="special">++</span><span class="identifier">left_iter</span> <span class="special">)</span> | |
186 | <span class="special">{</span> | |
187 | <span class="comment">// left_iter->first : key : int</span> | |
188 | <span class="comment">// left_iter->second : data : std::string</span> | |
189 | ||
190 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">left_iter</span><span class="special">-></span><span class="identifier">first</span> <span class="special"><<</span> <span class="string">" --> "</span> <span class="special"><<</span> <span class="identifier">left_iter</span><span class="special">-></span><span class="identifier">second</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
191 | <span class="special">}</span> | |
192 | ||
193 | <a class="co" name="boost_bimap.one_minute_tutorial.c2" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.c3"><img src="../../../../../doc/src/images/callouts/2.png" alt="2" border="0"></a><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_const_iterator</span> <span class="identifier">left_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="number">2</span><span class="special">);</span> | |
194 | <span class="identifier">assert</span><span class="special">(</span> <span class="identifier">left_iter</span><span class="special">-></span><span class="identifier">second</span> <span class="special">==</span> <span class="string">"two"</span> <span class="special">);</span> | |
195 | ||
196 | <a class="co" name="boost_bimap.one_minute_tutorial.c4" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.c5"><img src="../../../../../doc/src/images/callouts/3.png" alt="3" border="0"></a><span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</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">left_value_type</span><span class="special">(</span> <span class="number">3</span><span class="special">,</span> <span class="string">"three"</span> <span class="special">)</span> <span class="special">);</span> | |
197 | </pre> | |
198 | <p> | |
199 | </p> | |
200 | <div class="calloutlist"><table border="0" summary="Callout list"> | |
201 | <tr> | |
202 | <td width="5%" valign="top" align="left"><p><a name="boost_bimap.one_minute_tutorial.c1"></a><a href="#boost_bimap.one_minute_tutorial.c0"><img src="../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a> </p></td> | |
203 | <td valign="top" align="left"><p> | |
204 | The type of <code class="computeroutput"><span class="identifier">bm</span><span class="special">.</span><span class="identifier">left</span></code> is <code class="computeroutput"><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_map</span></code> | |
205 | and the type of <code class="computeroutput"><span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span></code> is <code class="computeroutput"><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">right_map</span></code> | |
206 | </p></td> | |
207 | </tr> | |
208 | <tr> | |
209 | <td width="5%" valign="top" align="left"><p><a name="boost_bimap.one_minute_tutorial.c3"></a><a href="#boost_bimap.one_minute_tutorial.c2"><img src="../../../../../doc/src/images/callouts/2.png" alt="2" border="0"></a> </p></td> | |
210 | <td valign="top" align="left"><p> | |
211 | <code class="computeroutput"><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_</span></code>-type- can be used as a shortcut | |
212 | for the more verbose <code class="computeroutput"><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_map</span><span class="special">::</span></code>-type- | |
213 | </p></td> | |
214 | </tr> | |
215 | <tr> | |
216 | <td width="5%" valign="top" align="left"><p><a name="boost_bimap.one_minute_tutorial.c5"></a><a href="#boost_bimap.one_minute_tutorial.c4"><img src="../../../../../doc/src/images/callouts/3.png" alt="3" border="0"></a> </p></td> | |
217 | <td valign="top" align="left"><p> | |
218 | This line produces the same effect of <code class="computeroutput"><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">3</span><span class="special">,</span><span class="string">"three"</span><span class="special">)</span> | |
219 | <span class="special">);</span></code> | |
220 | </p></td> | |
221 | </tr> | |
222 | </table></div> | |
223 | <h4> | |
224 | <a name="boost_bimap.one_minute_tutorial.h5"></a> | |
225 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.the_right_map_view"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.the_right_map_view">The | |
226 | right map view</a> | |
227 | </h4> | |
228 | <p> | |
229 | <code class="computeroutput"><span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span></code> works like a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span> | |
230 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">,</span> <span class="keyword">int</span> <span class="special">></span></code>. It | |
231 | is important to note that the key is the first type and the data is the second | |
232 | one, exactly as with standard maps. | |
233 | </p> | |
234 | <p> | |
235 | </p> | |
236 | <pre class="programlisting"><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">right_const_iterator</span> <span class="identifier">right_iter</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">"two"</span><span class="special">);</span> | |
237 | ||
238 | <span class="comment">// right_iter->first : key : std::string</span> | |
239 | <span class="comment">// right_iter->second : data : int</span> | |
240 | ||
241 | <span class="identifier">assert</span><span class="special">(</span> <span class="identifier">right_iter</span><span class="special">-></span><span class="identifier">second</span> <span class="special">==</span> <span class="number">2</span> <span class="special">);</span> | |
242 | ||
243 | <span class="identifier">assert</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">at</span><span class="special">(</span><span class="string">"one"</span><span class="special">)</span> <span class="special">==</span> <span class="number">1</span> <span class="special">);</span> | |
244 | ||
245 | <span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</span><span class="special">.</span><span class="identifier">erase</span><span class="special">(</span><span class="string">"two"</span><span class="special">);</span> | |
246 | ||
247 | <a class="co" name="boost_bimap.one_minute_tutorial.c6" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.c7"><img src="../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a><span class="identifier">bm</span><span class="special">.</span><span class="identifier">right</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">right_value_type</span><span class="special">(</span> <span class="string">"four"</span><span class="special">,</span> <span class="number">4</span> <span class="special">)</span> <span class="special">);</span> | |
248 | </pre> | |
249 | <p> | |
250 | </p> | |
251 | <div class="calloutlist"><table border="0" summary="Callout list"><tr> | |
252 | <td width="5%" valign="top" align="left"><p><a name="boost_bimap.one_minute_tutorial.c7"></a><a href="#boost_bimap.one_minute_tutorial.c6"><img src="../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a> </p></td> | |
253 | <td valign="top" align="left"><p> | |
254 | This line produces the same effect of <code class="computeroutput"><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">4</span><span class="special">,</span><span class="string">"four"</span><span class="special">)</span> | |
255 | <span class="special">);</span></code> | |
256 | </p></td> | |
257 | </tr></table></div> | |
258 | <h4> | |
259 | <a name="boost_bimap.one_minute_tutorial.h6"></a> | |
260 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.differences_with_std__map"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.differences_with_std__map">Differences | |
261 | with std::map</a> | |
262 | </h4> | |
263 | <p> | |
264 | The main difference between bimap views and their standard containers counterparts | |
265 | is that, because of the bidirectional nature of a bimap, the values stored | |
266 | in it can not be modified directly using iterators. For example, when a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="identifier">X</span><span class="special">,</span><span class="identifier">Y</span><span class="special">></span></code> iterator | |
267 | is dereferenced the return type is <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">X</span><span class="special">,</span> | |
268 | <span class="identifier">Y</span><span class="special">></span></code>, | |
269 | so the following code is valid: <code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">begin</span><span class="special">()-></span><span class="identifier">second</span> <span class="special">=</span> <span class="identifier">new_value</span><span class="special">;</span></code>. | |
270 | However dereferencing a <code class="computeroutput"><span class="identifier">bimap</span><span class="special"><</span><span class="identifier">X</span><span class="special">,</span><span class="identifier">Y</span><span class="special">>::</span><span class="identifier">left_iterator</span></code> | |
271 | returns a type that is <span class="emphasis"><em>signature-compatible</em></span> with a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">X</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">Y</span><span class="special">></span></code> | |
272 | </p> | |
273 | <pre class="programlisting"><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><span class="identifier">second</span> <span class="special">=</span> <span class="string">"1"</span><span class="special">;</span> <span class="comment">// Compilation error</span> | |
274 | </pre> | |
275 | <p> | |
276 | If you insert <code class="computeroutput"><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="string">"one"</span><span class="special">)</span></code> 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> in a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</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> the second insertion will have no effect. | |
277 | In a <code class="computeroutput"><span class="identifier">bimap</span><span class="special"><</span><span class="identifier">X</span><span class="special">,</span><span class="identifier">Y</span><span class="special">></span></code> both keys have to remain unique. The insertion | |
278 | may fail in other situations too. Lets see an example | |
279 | </p> | |
280 | <pre class="programlisting"><span class="identifier">bm</span><span class="special">.</span><span class="identifier">clear</span><span class="special">();</span> | |
281 | ||
282 | <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> | |
283 | ||
284 | <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">"1"</span> <span class="special">)</span> <span class="special">);</span> <span class="comment">// No effect!</span> | |
285 | <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">"one"</span> <span class="special">)</span> <span class="special">);</span> <span class="comment">// No effect!</span> | |
286 | ||
287 | <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> | |
288 | </pre> | |
289 | <h4> | |
290 | <a name="boost_bimap.one_minute_tutorial.h7"></a> | |
291 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.a_simple_example"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.a_simple_example">A | |
292 | simple example</a> | |
293 | </h4> | |
294 | <p> | |
295 | Look how you can reuse code that is intend to be used with std::maps, like | |
296 | the print_map function in this example. | |
297 | </p> | |
298 | <p> | |
299 | <a href="../../../example/simple_bimap.cpp" target="_top">Go to source code</a> | |
300 | </p> | |
301 | <p> | |
302 | </p> | |
303 | <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">string</span><span class="special">></span> | |
304 | <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> | |
305 | ||
306 | <span class="preprocessor">#include</span> <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">hpp</span><span class="special">></span> | |
307 | ||
308 | <span class="keyword">template</span><span class="special"><</span> <span class="keyword">class</span> <span class="identifier">MapType</span> <span class="special">></span> | |
309 | <span class="keyword">void</span> <span class="identifier">print_map</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">MapType</span> <span class="special">&</span> <span class="identifier">map</span><span class="special">,</span> | |
310 | <span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">&</span> <span class="identifier">separator</span><span class="special">,</span> | |
311 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">ostream</span> <span class="special">&</span> <span class="identifier">os</span> <span class="special">)</span> | |
312 | <span class="special">{</span> | |
313 | <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">MapType</span><span class="special">::</span><span class="identifier">const_iterator</span> <span class="identifier">const_iterator</span><span class="special">;</span> | |
314 | ||
315 | <span class="keyword">for</span><span class="special">(</span> <span class="identifier">const_iterator</span> <span class="identifier">i</span> <span class="special">=</span> <span class="identifier">map</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">iend</span> <span class="special">=</span> <span class="identifier">map</span><span class="special">.</span><span class="identifier">end</span><span class="special">();</span> <span class="identifier">i</span> <span class="special">!=</span> <span class="identifier">iend</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span> <span class="special">)</span> | |
316 | <span class="special">{</span> | |
317 | <span class="identifier">os</span> <span class="special"><<</span> <span class="identifier">i</span><span class="special">-></span><span class="identifier">first</span> <span class="special"><<</span> <span class="identifier">separator</span> <span class="special"><<</span> <span class="identifier">i</span><span class="special">-></span><span class="identifier">second</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
318 | <span class="special">}</span> | |
319 | <span class="special">}</span> | |
320 | ||
321 | <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> | |
322 | <span class="special">{</span> | |
323 | <span class="comment">// Soccer World cup</span> | |
324 | ||
325 | <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</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="keyword">int</span> <span class="special">></span> <span class="identifier">results_bimap</span><span class="special">;</span> | |
326 | <span class="keyword">typedef</span> <span class="identifier">results_bimap</span><span class="special">::</span><span class="identifier">value_type</span> <span class="identifier">position</span><span class="special">;</span> | |
327 | ||
328 | <span class="identifier">results_bimap</span> <span class="identifier">results</span><span class="special">;</span> | |
329 | <span class="identifier">results</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">position</span><span class="special">(</span><span class="string">"Argentina"</span> <span class="special">,</span><span class="number">1</span><span class="special">)</span> <span class="special">);</span> | |
330 | <span class="identifier">results</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">position</span><span class="special">(</span><span class="string">"Spain"</span> <span class="special">,</span><span class="number">2</span><span class="special">)</span> <span class="special">);</span> | |
331 | <span class="identifier">results</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">position</span><span class="special">(</span><span class="string">"Germany"</span> <span class="special">,</span><span class="number">3</span><span class="special">)</span> <span class="special">);</span> | |
332 | <span class="identifier">results</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span> <span class="identifier">position</span><span class="special">(</span><span class="string">"France"</span> <span class="special">,</span><span class="number">4</span><span class="special">)</span> <span class="special">);</span> | |
333 | ||
334 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"The number of countries is "</span> <span class="special"><<</span> <span class="identifier">results</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span> | |
335 | <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
336 | ||
337 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"The winner is "</span> <span class="special"><<</span> <span class="identifier">results</span><span class="special">.</span><span class="identifier">right</span><span class="special">.</span><span class="identifier">at</span><span class="special">(</span><span class="number">1</span><span class="special">)</span> | |
338 | <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span> | |
339 | <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
340 | ||
341 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Countries names ordered by their final position:"</span> | |
342 | <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
343 | ||
344 | <span class="comment">// results.right works like a std::map< int, std::string ></span> | |
345 | ||
346 | <span class="identifier">print_map</span><span class="special">(</span> <span class="identifier">results</span><span class="special">.</span><span class="identifier">right</span><span class="special">,</span> <span class="string">") "</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">);</span> | |
347 | ||
348 | <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span> | |
349 | <span class="special"><<</span> <span class="string">"Countries names ordered alphabetically along with"</span> | |
350 | <span class="string">"their final position:"</span> | |
351 | <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> | |
352 | ||
353 | <span class="comment">// results.left works like a std::map< std::string, int ></span> | |
354 | ||
355 | <span class="identifier">print_map</span><span class="special">(</span> <span class="identifier">results</span><span class="special">.</span><span class="identifier">left</span><span class="special">,</span> <span class="string">" ends in position "</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">);</span> | |
356 | ||
357 | <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> | |
358 | <span class="special">}</span> | |
359 | </pre> | |
360 | <p> | |
361 | </p> | |
362 | <p> | |
363 | The output of this program will be the following: | |
364 | </p> | |
365 | <pre class="programlisting"><code class="literal">The number of countries is 4</code> | |
366 | ||
367 | <code class="literal">The winner is Argentina</code> | |
368 | ||
369 | <code class="literal">Countries names ordered by their final position:</code> | |
370 | <code class="literal">1) Argentina</code> | |
371 | <code class="literal">2) Spain</code> | |
372 | <code class="literal">3) Germany</code> | |
373 | <code class="literal">4) France</code> | |
374 | ||
375 | <code class="literal">Countries names ordered alphabetically along with their final position:</code> | |
376 | <code class="literal">Argentina ends in position 1</code> | |
377 | <code class="literal">France ends in position 4</code> | |
378 | <code class="literal">Germany ends in position 3</code> | |
379 | <code class="literal">Spain ends in position 2</code> | |
380 | </pre> | |
381 | <h4> | |
382 | <a name="boost_bimap.one_minute_tutorial.h8"></a> | |
383 | <span class="phrase"><a name="boost_bimap.one_minute_tutorial.continuing_the_journey"></a></span><a class="link" href="one_minute_tutorial.html#boost_bimap.one_minute_tutorial.continuing_the_journey">Continuing | |
384 | the journey</a> | |
385 | </h4> | |
386 | <p> | |
387 | For information on function signatures, see any standard library documentation | |
388 | or read the <a class="link" href="reference.html" title="Reference">reference</a> section | |
389 | of this documentation. | |
390 | </p> | |
391 | <div class="caution"><table border="0" summary="Caution"> | |
392 | <tr> | |
393 | <td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../../../../../doc/src/images/caution.png"></td> | |
394 | <th align="left">Caution</th> | |
395 | </tr> | |
396 | <tr><td align="left" valign="top"><p> | |
397 | Be aware that a bidirectional map is only signature-compatible with standard | |
398 | containers. Some functions may give different results, such as in the case | |
399 | of inserting a pair into the left map where the second value conflicts with | |
400 | a stored relation in the container. The functions may be slower in a bimap | |
401 | because of the duplicated constraints. It is strongly recommended that you | |
402 | read <a class="link" href="the_tutorial.html" title="The tutorial">The full tutorial</a> if | |
403 | you intend to use a bimap in a serious project. | |
404 | </p></td></tr> | |
405 | </table></div> | |
406 | <div class="footnotes"> | |
407 | <br><hr style="width:100; align:left;"> | |
408 | <div id="ftn.boost_bimap.one_minute_tutorial.f0" class="footnote"><p><a href="#boost_bimap.one_minute_tutorial.f0" class="para"><sup class="para">[1] </sup></a> | |
409 | A type is <span class="emphasis"><em>signature-compatible</em></span> with other type if it | |
410 | has the same signature for functions and metadata. Preconditions, postconditions | |
411 | and the order of operations need not be the same. | |
412 | </p></div> | |
413 | </div> | |
414 | </div> | |
415 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
416 | <td align="left"></td> | |
417 | <td align="right"><div class="copyright-footer">Copyright © 2006-2012 Matias Capeletto<p> | |
418 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
419 | 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>) | |
420 | </p> | |
421 | </div></td> | |
422 | </tr></table> | |
423 | <hr> | |
424 | <div class="spirit-nav"> | |
425 | <a accesskey="p" href="introduction.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="the_tutorial.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> | |
426 | </div> | |
427 | </body> | |
428 | </html> |