ment">// <a class="link" href="counting_iterator.html#idp53391840-bb">public member functions</a></span>
  <span class="identifier">size_t</span> <a class="link" href="counting_iterator.html#idp53392400-bb"><span class="identifier">get_index</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Expr<span class="special