yword">struct</span> <span class="identifier">pair</span>
<span class="special">{</span>
<span class="keyword">typedef</span> <span class="identifier">T1</span> <span class="identifier">first_type</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">T2</span> <span class="identifier">second_type</span><span class="special">;</span>

<span class="identifier">T1</span> <span class="identifier">first</span><span class="special">;</span>
<span class="identifier">T2<