ition for <code class="computeroutput"><span class="identifier">pair</span></code>
      that can contain non-reference types, reference types, and constant reference
      types:
    </p>
<pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T1</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">T2</span><span class="special">&gt;</span>
<span class="ke