identifier">filter_iterator</span><span class="special">&amp;</span> <span class="keyword">operator</span><span class="special">++();</span>
<span class="keyword">private</span><span class="special">:</span>
    <span class="identifier">Predicate</span> <span class="identifier">m_pred</span><span class="special">;</span> <span class="comment">// exposition only</span>
    <span class="identifier">Iterator</span> <span class="identifier">m_iter</span><span class="special">;</span>  <span class="comment">// e