title: append set to another set
body: <p>Is there a better way of appending a set to another set than iterating through each element ?</p>
  
  <p>i have :</p>
  
  <pre><code>set&lt;string&gt; foo ;
  set&lt;string&gt; bar ;
  
  .....
  
  for (set&lt;string&gt;::const_iterator p = foo.begin( );p != foo.end( ); ++p)
      bar.insert(*p);
  </code></pre>
  
  <p>Is there a more efficient way to do this ?</p>