</span><span class="k">struct</span> <span class="n">counter</span>
<span class="p">{</span>
    <span class="kt">int</span> <span class="n">i</span><span class="p">;</span>
    <span class="n">counter</span><span class="p">()</span> <span class="o">:</span> <span class="n">i</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
    <span class="p">{}</span>

    <span class="k">template</span><span class="o">&lt;</span><span class="n">class</span><span class="p">...</span> <span c