My experience with programming is: make it work first, do the GUI later. Many times has this spared me headaches. But for a very complex program, sometimes working on a GUI and the programming itself side-by-side could be working too, as changing the code for implementing a GUI later, does give you headaches. Then again, how complex this is, I'm not sure. If I could script this in Pascal, it would seem very easy. It would only be changing a few lines in a text-file for the program to do (assigning file, open file, reading input, change/add line, close file).... how to do that, is fairly simple, I guess. But the choice what to change, is probably more a variable of extreme importance. when you need an indicator of how much work it would be, then the difficulty of the work, in this case.