title: Case Insensitive String Comparison in C
body: <p>I have two postcodes <code>char*</code> that I want to compare, ignoring case.
  Is there a function to do this?</p>
  <p>Or do I have to loop through each use the <code>tolower</code> function and then do the comparison?</p>
  <p>Any idea how this function will react with numbers in the string</p>
  <p>Thanks</p>