title: What is the default unit of time of c++'s chrono?
body: <p>I used this code to measure the runtime of my program from <a href="https://stackoverflow.com/a/11062846/3127121">this answer</a></p>
  
  <pre><code>auto start = std::chrono::system_clock::now();
  
  /* do some work */
  
  auto end = std::chrono::system_clock::now();
  auto elapsed = end - start;
  std::cout &lt;&lt; elapsed.count() &lt;&lt; '\n';
  </code></pre>
  
  <p>I only needed to measure the runtime to look for a trend but I am kind of curious as to what unit that is.</p>