title: Which functions from the standard library must (should) be avoided?
body: <p>I've read on Stack Overflow that some C functions are "obsolete" or "should be avoided". Can you please give me some examples of this kind of function and the reason why?</p>
  
  <p>What alternatives to those functions exist?</p>
  
  <p>Can we use them safely - any good practices?</p>