title: Find most common element in array
body: <p>I have a string array that can contains 1 or more elements with various string values.  I need to find the most common string in the array.</p>
  
  <pre><code>string aPOS[] = new string[]{"11","11","18","18","11","11"};
  </code></pre>
  
  <p>I need to return <code>"11"</code> in this case.</p>