Timer or Stopwatch?

A well known feature of Qt framework (at least what I guess) is the QTimer class, which essentially allows to have repetitive tasks or calculations at a given time interval. Think of it as a timer, that when it goes off, sends the timeout() signal and starts again the countdown for another interval. But a less known feature (at least what I guess) is the QElapsedTimer class, which acts the opposite: once started, you can know the elapsed time since that moment by calling the ellapsed() method.