d="l00137" name="l00137"></a><span class="lineno">  137</span>{</div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span>    <span class="keyword">typename</span> vector_of&lt;T&gt;::type c;</div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span>    c.x = (box.upper.x + box.lower.x) * 0.5;</div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span>    c.y = (box.upper.y + box.lower.y) * 0.5;</div>
<div class="