title: Regex: "password must have at least 3 of the 4 of the following"
body: <p>I'm a Regex newbie, and so far have only used it for simple things, like "must be a number or letter". Now I have to do something a bit more complex. </p>
  
  <p>I need to use it to validate a password, which must be 8-16 characters, free of control/non-printing/non-ASCII characters, and must have at least three of the following:</p>
  
  <ul>
  <li>one capital letter</li>
  <li>one lowercase letter</li>
  <li>one number 0-9</li>
  <li>one symbol character ($, %, &amp;, etc.)</li>
  </ul>
  
  <p>I'm thinking what I have to do is write something like "one capital letter, lowercase letter and number, OR one capital letter, lowercase letter and one symbol, OR one capital letter, one number or one symbol, OR...." to cover all possible "3 out of 4" combinations, but that seems excessive. Is there a simpler solution?</p>