title: how to initialize a QString to null?
body: <p>What is the difference between <code>QString::number(0)</code> and <code>((const char*) 0)</code>?</p>
  
  <p>I want to initialize a <code>QString</code> say <code>phoneNumber</code> to <code>null</code>. Will <code>phoneNumber(QString::number(0))</code> and <code>phoneNumber((const char*) 0)</code> both work?</p>