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  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="geometry.reference.algorithms.num_points"></a><a class="link" href="num_points.html" title="num_points">num_points</a>
  28 </h4></div></div></div>
  29 <p>
  30           <a class="indexterm" name="idp119214144"></a>
  31 Calculates the number of points of a geometry.
  32         </p>
  33 <h6>
  34 <a name="geometry.reference.algorithms.num_points.h0"></a>
  35           <span class="phrase"><a name="geometry.reference.algorithms.num_points.description"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.description">Description</a>
  36         </h6>
  37 <p>
  38           The free function num_points calculates the number of points of a geometry.
  39         </p>
  40 <h6>
  41 <a name="geometry.reference.algorithms.num_points.h1"></a>
  42           <span class="phrase"><a name="geometry.reference.algorithms.num_points.synopsis"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.synopsis">Synopsis</a>
  43         </h6>
  44 <p>
  45 </p>
  46 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Geometry</span><span class="special">&gt;</span>
  47 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">num_points</span><span class="special">(</span><span class="identifier">Geometry</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">geometry</span><span class="special">,</span> <span class="keyword">bool</span> <span class="identifier">add_for_open</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">)</span></pre>
  48 <p>
  49         </p>
  50 <h6>
  51 <a name="geometry.reference.algorithms.num_points.h2"></a>
  52           <span class="phrase"><a name="geometry.reference.algorithms.num_points.parameters"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.parameters">Parameters</a>
  53         </h6>
  54 <div class="informaltable"><table class="table">
  55 <colgroup>
  56 <col>
  57 <col>
  58 <col>
  59 <col>
  60 </colgroup>
  61 <thead><tr>
  62 <th>
  63                   <p>
  64                     Type
  65                   </p>
  66                 </th>
  67 <th>
  68                   <p>
  69                     Concept
  70                   </p>
  71                 </th>
  72 <th>
  73                   <p>
  74                     Name
  75                   </p>
  76                 </th>
  77 <th>
  78                   <p>
  79                     Description
  80                   </p>
  81                 </th>
  82 </tr></thead>
  83 <tbody>
  84 <tr>
  85 <td>
  86                   <p>
  87                     Geometry const &amp;
  88                   </p>
  89                 </td>
  90 <td>
  91                   <p>
  92                     Any type fulfilling a Geometry Concept
  93                   </p>
  94                 </td>
  95 <td>
  96                   <p>
  97                     geometry
  98                   </p>
  99                 </td>
 100 <td>
 101                   <p>
 102                     A model of the specified concept
 103                   </p>
 104                 </td>
 105 </tr>
 106 <tr>
 107 <td>
 108                   <p>
 109                     bool
 110                   </p>
 111                 </td>
 112 <td>
 113                 </td>
 114 <td>
 115                   <p>
 116                     add_for_open
 117                   </p>
 118                 </td>
 119 <td>
 120                   <p>
 121                     add one for open geometries (i.e. polygon types which are not
 122                     closed)
 123                   </p>
 124                 </td>
 125 </tr>
 126 </tbody>
 127 </table></div>
 128 <h6>
 129 <a name="geometry.reference.algorithms.num_points.h3"></a>
 130           <span class="phrase"><a name="geometry.reference.algorithms.num_points.returns"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.returns">Returns</a>
 131         </h6>
 132 <p>
 133           The calculated number of points
 134         </p>
 135 <h6>
 136 <a name="geometry.reference.algorithms.num_points.h4"></a>
 137           <span class="phrase"><a name="geometry.reference.algorithms.num_points.header"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.header">Header</a>
 138         </h6>
 139 <p>
 140           Either
 141         </p>
 142 <p>
 143           <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 144         </p>
 145 <p>
 146           Or
 147         </p>
 148 <p>
 149           <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">algorithms</span><span class="special">/</span><span class="identifier">num_points</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 150         </p>
 151 <h6>
 152 <a name="geometry.reference.algorithms.num_points.h5"></a>
 153           <span class="phrase"><a name="geometry.reference.algorithms.num_points.conformance"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.conformance">Conformance</a>
 154         </h6>
 155 <p>
 156           The function num_points implements function NumPoints from the <a href="http://www.opengeospatial.org/standards/sfa" target="_top">OGC
 157           Simple Feature Specification</a>.
 158         </p>
 159 <div class="note"><table border="0" summary="Note">
 160 <tr>
 161 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../doc/src/images/note.png"></td>
 162 <th align="left">Note</th>
 163 </tr>
 164 <tr><td align="left" valign="top"><p>
 165             num_points can be called for any geometry and not just linestrings (as
 166             the standard describes)
 167           </p></td></tr>
 168 </table></div>
 169 <h6>
 170 <a name="geometry.reference.algorithms.num_points.h6"></a>
 171           <span class="phrase"><a name="geometry.reference.algorithms.num_points.behavior"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.behavior">Behavior</a>
 172         </h6>
 173 <div class="informaltable"><table class="table">
 174 <colgroup>
 175 <col>
 176 <col>
 177 </colgroup>
 178 <thead><tr>
 179 <th>
 180                   <p>
 181                     Case
 182                   </p>
 183                 </th>
 184 <th>
 185                   <p>
 186                     Behavior
 187                   </p>
 188                 </th>
 189 </tr></thead>
 190 <tbody>
 191 <tr>
 192 <td>
 193                   <p>
 194                     Point
 195                   </p>
 196                 </td>
 197 <td>
 198                   <p>
 199                     Returns 1
 200                   </p>
 201                 </td>
 202 </tr>
 203 <tr>
 204 <td>
 205                   <p>
 206                     Segment
 207                   </p>
 208                 </td>
 209 <td>
 210                   <p>
 211                     Returns 2
 212                   </p>
 213                 </td>
 214 </tr>
 215 <tr>
 216 <td>
 217                   <p>
 218                     Box
 219                   </p>
 220                 </td>
 221 <td>
 222                   <p>
 223                     Returns 2^d, where d is the dimension of the box
 224                   </p>
 225                 </td>
 226 </tr>
 227 <tr>
 228 <td>
 229                   <p>
 230                     Rangelike (linestring, ring)
 231                   </p>
 232                 </td>
 233 <td>
 234                   <p>
 235                     Returns boost::size(geometry)
 236                   </p>
 237                 </td>
 238 </tr>
 239 <tr>
 240 <td>
 241                   <p>
 242                     Other geometries
 243                   </p>
 244                 </td>
 245 <td>
 246                   <p>
 247                     Returns the sum of the number of points of its elements
 248                   </p>
 249                 </td>
 250 </tr>
 251 <tr>
 252 <td>
 253                   <p>
 254                     Open geometries
 255                   </p>
 256                 </td>
 257 <td>
 258                   <p>
 259                     Returns the sum of the number of points of its elements, it adds
 260                     one for open (per ring) if specified
 261                   </p>
 262                 </td>
 263 </tr>
 264 <tr>
 265 <td>
 266                   <p>
 267                     Closed geometries
 268                   </p>
 269                 </td>
 270 <td>
 271                   <p>
 272                     Returns the sum of the number of points of its elements
 273                   </p>
 274                 </td>
 275 </tr>
 276 </tbody>
 277 </table></div>
 278 <h6>
 279 <a name="geometry.reference.algorithms.num_points.h7"></a>
 280           <span class="phrase"><a name="geometry.reference.algorithms.num_points.complexity"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.complexity">Complexity</a>
 281         </h6>
 282 <p>
 283           Constant or Linear
 284         </p>
 285 <h6>
 286 <a name="geometry.reference.algorithms.num_points.h8"></a>
 287           <span class="phrase"><a name="geometry.reference.algorithms.num_points.examples"></a></span><a class="link" href="num_points.html#geometry.reference.algorithms.num_points.examples">Examples</a>
 288         </h6>
 289 <p>
 290           Get the number of points in a geometry
 291         </p>
 292 <p>
 293 </p>
 294 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
 295
 296 <span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 297 <span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">/</span><span class="identifier">point_xy</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 298 <span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">/</span><span class="identifier">polygon</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 299 <span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">/</span><span class="identifier">multi_polygon</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 300
 301
 302 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
 303 <span class="special">{</span>
 304     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">multi_polygon</span>
 305         <span class="special">&lt;</span>
 306             <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">polygon</span>
 307                 <span class="special">&lt;</span>
 308                     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">d2</span><span class="special">::</span><span class="identifier">point_xy</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;</span>
 309                 <span class="special">&gt;</span>
 310         <span class="special">&gt;</span> <span class="identifier">mp</span><span class="special">;</span>
 311     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">read_wkt</span><span class="special">(</span><span class="string">"MULTIPOLYGON(((0 0,0 10,10 0,0 0),(1 1,1 9,9 1,1 1)),((10 10,10 7,7 10,10 10)))"</span><span class="special">,</span> <span class="identifier">mp</span><span class="special">);</span>
 312     <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"Number of points: "</span> <span class="special">&lt;&lt;</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">num_points</span><span class="special">(</span><span class="identifier">mp</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
 313
 314     <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
 315 <span class="special">}</span>
 316 </pre>
 317 <p>
 318         </p>
 319 <p>
 320           Output:
 321         </p>
 322 <pre class="programlisting">Number of points: 12
 323 </pre>
 324 </div>
 325 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 326 <td align="left"></td>
 327 <td align="right"><div class="copyright-footer">Copyright &#169; 2009-2014 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam
 328       Wulkiewicz, Oracle and/or its affiliates<p>
 329         Distributed under the Boost Software License, Version 1.0. (See accompanying
 330         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>)
 331       </p>
 332 </div></td>
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