title: How to unset a specific bit in an integer
body: <p>Say, I have a integer like <code>10101</code>, I would like to unset the third bit to get <code>10001</code>; if I have <code>10001</code>, I will still get <code>10001</code>;  how can I achieve it? </p>
  
  <pre><code>unset(int i, int j)
  int i= 10101 or 10000
  int j = 00100
  </code></pre>