I am thinking of using a filetype of numbers (as text) separated by whitespace in one of my apps. Any kind of whitespace (space, line break, whatever) will do. I am curious if this is a standard file type? If so, what is it called?
Most programs seem to implement it as txt, and for a simple enough format, I think that would be fine.
If your intention is to allow access to the file from excel or ilk, I would reccomend using Tab characters (\t or 0x0b) to separate fields with newlines separating records. Name it either .tsv or .txt and you have Tab Separated Values.