title: Get longest substring between two strings
body: <p>I have two words,</p>
  
  <p><code>britanicaeng</code>  and
  <code>britanicahin</code></p>
  
  <p>I need to find out the longest common word between these i.e, <code>britanica</code>.</p>
  
  <p>How can I do this in C# ?</p>