title: Bitwise "and" operation into the kotlin
body: <p>If negative number is from -31 to -1 then I would like represent it into the format 111XXXXX.
  I try to do it using "and" bitwise operator:</p>
  
  <pre><code>println("0b00011111 &amp; 0xe0 is ${0b00011111 and 0xe0}")
  println("31 &amp; 0xe0 is ${31 and 0xe0}")
  println("0b00011111 &amp; 0b11100000 is ${0b00011111 and 0b11100000}")
  </code></pre>
  
  <p>But the result is always 0. Where did I make the mistake?</p>