title: how to execute an for loop till the queue is emptyin c++
body: <p>i need to execute an for loop till the queue is empty 
  my code</p>
  
  <pre><code>queue&lt;string&gt; q;
  for(int i=0;i&lt;q.size(),i++)
  {
       // some operation goes here
       // some datas are added to queue
  }
  </code></pre>