ey, then the second key if the first one is equal, etc. This
order allows for partial searches where only the first keys are specified:
</p>

<blockquote><pre>
<span class=identifier>phonebook</span> <span class=identifier>pb</span><span class=special>;</span>
<span class=special>...</span>
<span class=comment>// look for all Whites</span>
<span class=identifier>std</span><span class=special>::</span><span class=identifier>pair</span><span class=special>&lt;</span><span class=identifier>phonebook</span><spa