n class="comment">                class_type&amp; operator+= (T const &amp; x);</span></div>
<div class="line"><a name="l00127"></a><span class="lineno">  127</span>&#160;<span class="comment">                class_type&amp; operator+= (class_type const &amp; x);</span></div>
<div class="line"><a name="l00128"></a><span class="lineno">  128</span>&#160;<span class="comment">                class_type&amp; operator-= (T const &amp; x);</span></div>
<div class="line"><a name="l00129"></a><span class="lineno">