title: how to implement a circular counter?
body: <p>I want to make a circular counter in C programming.
     First variable can store value from 0-3.
     Second variable asks the value from user (from 0-3).
     Third variable asks user to move either left or right</p>
  
  <p>If third variable is left 
      the second variable should move left:</p>
  
  <pre><code>3-&gt;2
  2-&gt;1
  1-&gt;0
  0-&gt;3
  </code></pre>
  
  <p>Similarly if third variable is right
      the second variable should move right:</p>
  
  <pre><code>0-&gt;1
  1-&gt;2
  2-&gt;3
  3-&gt;0
  </code></pre>