Hello there. I've doing a program that I do not know how many files will be needed, because it'll depend on user's choice. So, how to name them? I tought that a command like, where n is a user-input number Code (Text): Do While (i .LE. n) Open (Unit=i, File=i'.dat') i=i+1 EndDo Would be enough, but I can't name my files this way. Any ideas?