Which file version do you mean exactly? Generally, files don't carry version information at the level of file systems. But of course, specific file formats could do that (consider e.g. a text file, with the first line saying "Interpreter.Version = 0.3" or something like that). There are versioning file systems, but this isn't reliable information for your program (except you are writing some low level piece of software, that is targetted at ext3fs, for example; or some other specific file system).

For Windows, take a look at the Version Information documentation.