thms.area.area_1.c1"><img src="../../../../../../../../doc/src/images/callouts/1.png" alt="1" border="0"></a>

<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
<span class="special">{</span>
    <span class="comment">// Calculate the area of a cartesian polygon</span>
    <span class="identifier">bg</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">polygon</span><span class="sp