 to the object. Clearly, there is no other choice.
        </p>
<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">x</span> <span class="special">=</span> <span class="number">1</span> <span class="special">;</span>
<span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">rx</span> <span class="special">=</span> <span class="identifier">x</span> <span class="special">;</span>
<span class="identifier">optional</span><span class="special">&