pecial">;</span>
<span class="identifier">at_key</span><span class="special">&lt;</span><span class="identifier">keys</span><span class="special">::</span><span class="identifier">age</span><span class="special">&gt;(</span><span class="identifier">e</span><span class="special">)=</span><span class="number">41</span><span class="special">;</span>
<span class="comment">//Prints 'Edward Norton is 41 years old'</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">co