o">   40</span><span class="comment">// Forward declarations</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="keyword">template</span> &lt;std::<span class="keywordtype">size_t</span> Columns, std::<span class="keywordtype">size_t</span> Rows&gt;</div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="keyword">struct </span>Matrix;</div>
<div class="line"><a id="l00043" name="l00043"></a><span class="