Thanks! yes, this goes to show the perils of coding after a 12h work day on Friday :-). This affected the use of fgets() I/O (I understood you have to call the line-buffered routines based on their description)
Enjoyed reading your code. Beautiful. Thanks!
Ok, I looked at your code. What you really should do (before coding up the solution) is to look at the problem specification. Other than that I like the 'direct' approach, it isn't quite as fast as what I cooked up but yours is a lot shorter.