I want to add some value to this situation …
Use UpCase(ReadKey);
That way you don't need to code the upper and lower cases for the test.
Also while in CRT mode/DOS the readkey will return a #0 if you hit a special key, when receiving one of these you should call ReadKey again to get the special key code that follows.
so if you are inclined to use the arrow keys for example this is where they work..
If Inner case statement works for this too.