class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">iterator_traits</span><span class="special">&lt;</span><span class="identifier">BidirectionalIterator</span><span class="special">&gt;::</span><span class="identifier">difference_type</span> <span class="identifier">difference_type</span><span class="special">;</span>
   <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">Allocator</span><span class="special">::</span