title: How do I measure time in C?
body: <p>I want to find out for how long (approximately) some block of code executes. Something like this:</p>
  
  <pre><code>startStopwatch();
  // do some calculations
  stopStopwatch();
  printf("%lf", timeMesuredInSeconds);
  </code></pre>
  
  <p>How?</p>