xposition only</span>
    <span class="identifier">Iterator</span> <span class="identifier">m_end</span><span class="special">;</span>   <span class="comment">// exposition only</span>
<span class="special">};</span>
</pre>
<p>
        If <code class="computeroutput"><span class="identifier">Iterator</span></code> models Readable
        Lvalue Iterator and Bidirectional Traversal Iterator then <code class="computeroutput"><span class="identifier">iterator_category</span></code>
        is convertible to <c