 including the necessary header files.
      </p>
<p>
        All of the asio classes can be used by simply including the <code class="computeroutput">"asio.hpp"</code>
        header file.
      </p>
<pre class="programlisting">#include &lt;iostream&gt;
#include &lt;boost/asio.hpp&gt;
</pre>
<p>
        Since this example uses timers, we need to include the appropriate Boost.Date_Time
        header file for manipulating times.
      </p>
<pre class="programlisting">#include &lt;boost/date_time/posix_time/