Did the compiling of the code that I posted in post #11 successfully compile
or
did you get a compiler-error?
If you got a compiler-error please provide the compiler-log like described here
If you had no compiler-error
As you worked as a trainer you had your trainee next to you for direct communication.
In a user-forum you have to replace the direct comunication with a very precise description of what you have observed when testing a new code-version.
So what happends if you load my code-version from post # 11 (do you recognise the details? I'm repeating the number of the post instead of writing just about "the code" which would be unprecise)
Does the code compile yes or no? etc. etc.
best regards Stefan