title: How to increment letters like numbers in PHP?
body: <p>I would like to write a function that takes in 3 characters and increments it and returns the newly incremented characters as a string.</p>
  
  <p>I know how to increase a single letter to the next one but how would I know when to increase the second letters and then stop and then increase the first letter again to have a sequential  increase?</p>
  
  <blockquote>
    <p>So if AAA is passed, return AAB. If
    AAZ is passed return ABA (hard part).</p>
  </blockquote>
  
  <p>I would appreciate help with the logic and what php functions will be useful to use.</p>
  
  <p>Even better, has some done this already or there is a class available to do this??</p>
  
  <p>Thanks all for any help</p>