title: controllers are created using a factory function?
body: <p>I am new to angularJS and going through angular docs.I came across this line <strong><a href="https://docs.angularjs.org/guide/concepts" rel="nofollow">controllers are created using a factory function</a></strong></p>
  
  <p>I tried to find what that means and found what is factory and service and providers but that does not fit here.
   How controllers are created using a factory function?</p>
  
  <p>Please explain what is the meaning of <strong>factory in this context</strong>.</p>