

    <span class="identifier">point_type</span> <span class="identifier">p</span><span class="special">(</span><span class="number">4</span><span class="special">,</span> <span class="number">1</span><span class="special">);</span>

    <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"within: "</span> <span class="special">&lt;&lt;</span> <span class="special">(</span><span class="identifier">b