d">bool</span> <span class="identifier">adder</span><span class="special">(</span><span class="identifier">Iterator</span> <span class="identifier">first</span><span class="special">,</span> <span class="identifier">Iterator</span> <span class="identifier">last</span><span class="special">,</span> <span class="keyword">double</span><span class="special">&amp;</span> <span class="identifier">n</span><span class="special">)</span>
<span class="special">{</span>
    <span class="keyword">auto</span> <span clas