I'm developing an application and I want to justify why I changed the location of some files from "c:\" to "%temp%". I think the best reason would be that not all windows computers have the "C:" drive. Is that true?
Yes, its true! Windows location could be in any letter drive. Even because you can have more than one OS installed in the same computer.
You also could have a computer without C: driver letter.
You can look to others Environment Variables.
It is true that you can have another name for the Windows home drive. However, you can use
%PROGRAMDATA% to find out where to put your files.
Windows has many other environment variables.
Regardless of whether there can be a Windows installation without a
C:, there definitely can be a Windows installation with a
C: where you can't write, for example because there's no directory on that drive where your application has write permission, or because that drive is full.
If you need to create temporary files, create them in the directory indicated by the
TEMP environment variable (i.e.