><span class="p">()</span> <span class="p">{</span>
    <span class="kt">int</span> <span class="n">r</span> <span class="o">=</span> <span class="n">boost</span><span class="o">::</span><span class="n">hof</span><span class="o">::</span><span class="n">flip</span><span class="p">(</span><span class="n">boost</span><span class="o">::</span><span class="n">hof</span><span class="o">::</span><span class="n">_</span> <span class="o">-</span> <span class="n">boost</span><span class="o">::</span><span class="n">