="special">-&gt;</span><span class="identifier">empty</span><span class="special">())</span>
        <span class="identifier">os</span> <span class="special">&lt;&lt;</span> <span class="string">"\n"</span><span class="special">;</span>
<span class="special">}</span>

<span class="keyword">int</span>
<span class="identifier">main</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">argc</span><span class="special">,</span> <span class="keyword">char</span><span class