title: What is the difference between "compile time" and "run time"?
body: <p>I do not understand what is meant by the terms "compile time" and "run time" (or "runtime"). </p>
  
  <p>I'm also a bit confused about what "value type" and "reference type" mean, and how they relate to the 'times mentioned above.</p>
  
  <p>Would someone please explain these things?</p>