an> length_t <span class="keyword">const</span> cols = 0;</div><div class="line"><a name="l00041"></a><span class="lineno">   41</span>&#160;        <span class="keyword">static</span> length_t <span class="keyword">const</span> rows = 0;</div><div class="line"><a name="l00042"></a><span class="lineno">   42</span>&#160;    };</div><div class="line"><a name="l00043"></a><span class="lineno">   43</span>&#160;</div><div class="line"><a name="l00044"></a><span class="lineno">   44</span>&#160;    <span class=