title: Checking if bit is not set
body: <p>If I use this:
  <code>if(value &amp; 4)</code> to check if the bit is set, then how do I check if the bit isn't set?</p>
  
  <p>I tried with
  <code>if(!value &amp; 4)</code> or <code>if(~value &amp; 4)</code> and <code>if(value ^ 4)</code> but none of them works.</p>