title: Difference between QObject::connect vs connect methods
body: <p>I am a newbie with Qt. Most of the times Qt developers need to use signals and slots for object communication. I have seen two ways of connecting signals and slots so far.</p>
  
  <pre><code>1)QObject::connect(scrollBar, SIGNAL(valueChanged(int)),label,  SLOT(setNum(int)));
  
  2)connect(scrollBar, SIGNAL(valueChanged(int)),label,  SLOT(setNum(int)));
  </code></pre>
  
  <p>What is the exact difference between both of them? Why do we have to prefix QObject in the first method?</p>