><span class="special">(</span><span class="identifier">numbers_</span><span class="special">);</span>

  <span class="comment">// Example using filter_iterator</span>
  <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">filter_iterator</span><span class="special">&lt;</span><span class="identifier">is_positive_number</span><span class="special">,</span> <span class="identifier">base_iterator</span><span class="special">&gt;</spa