class="keyword">private</span><span class="special">:</span>
   <span class="identifier">T</span> <span class="identifier">a</span><span class="special">,</span> <span class="identifier">b</span><span class="special">;</span>
<span class="keyword">public</span><span class="special">:</span>
   <span class="identifier">tan_fraction</span><span class="special">(</span><span class="identifier">T</span> <span class="identifier">v</span><span class="special">)</span>
      <span class="special">:</span> <span cl