> <span class="keyword">int</span> <span class="identifier">sub</span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="keyword">const</span><span class="special">;</span>
<span class="identifier">difference_type</span> <span class="identifier">position</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_type</span><span class="special">*</span> <span class="identifier">sub</span><span class="special">)</s