<span class="identifier">ConstPolygonRingIterator</span> <span class="identifier">cbegin</span><span class="special">()</span> <span class="keyword">const</span>
    <span class="special">{</span>
        <span class="identifier">assert</span><span class="special">(</span><span class="identifier">isCIterSet</span><span class="special">);</span>
        <span class="keyword">return</span> <span class="identifier">_cbegin</span><span class="special">;</span>
    <span class="special">}</span>

    <span class