title: php increment letters results in infinite loop
body: <p>Im having trouble figuring out if this is a PHP "feature" or bug.</p>
  
  <p>Making a loop like this:</p>
  
  <pre class="lang-php prettyprint-override"><code>// PHP code
  for($i='A1';$i&lt;='c1';$i++){
  //something here..
  }
  </code></pre>
  
  <p>results in a infinite loop.
  Why is this happening?
  c1 should be "less" than A1
  or at least when A1 reaches C1 they should be equal.</p>
  
  <p>However. what happens is that $i goes all the way to Z1..Z9 and then turs to AA0...etc.</p>