   a <code class="computeroutput"><span class="identifier">filter_iterator</span></code> whose<code class="computeroutput"><span class="identifier">m_pred</span></code>, <code class="computeroutput"><span class="identifier">m_iter</span></code>,
        and <code class="computeroutput"><span class="identifier">m_end</span></code> members are a default
        constructed.
      </p>
<pre class="programlisting"><span class="identifier">filter_iterator</span><span class="special">(</span><span class="identifi