/span><span class="special">(</span><span class="identifier">query_box</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">result_s</span><span class="special">));</span>

    <span class="comment">// find 5 nearest values to a point</span>
    <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class