 <span class="identifier">sv</span><span class="special">;</span>
   <span class="identifier">sv</span><span class="special">.</span><span class="identifier">resize</span><span class="special">(</span><span class="number">100</span><span class="special">);</span>

   <span class="comment">//Let's build a tree based in</span>
   <span class="comment">//a recursive data type</span>
   <span class="identifier">tree_node</span> <span class="identifier">root</span><span class="special">;</span>
   <span class="i