title: Qt: format an integer in a QString
body: <p>I would like to format an integer in a <code>QString</code>. I would like to always have 6 numbers.
  For example "1" should be "000001" and "12" should be "000012".</p>
  
  <p>I try to do like with <code>printf(%06d, number)</code>. So I wrote this </p>
  
  <p><code>QString test;
   test = QString("%06d").arg(QString::number(i));
   qDebug()&lt;&lt;test;</code> </p>
  
  <p>i is implemented in a loop <code>for</code>.
  But it does not work since I have:</p>
  
  <blockquote>
    <p>"0d" 
    "1d"
    "2d"
    "3d"...</p>
  </blockquote>
  
  <p>Does anyone know how to do this please?</p>