Instead of declaring the character layout, declare month to be an array of pointers:
char *month[12];
Then in the routine where you want to initialize the values,
month[0] = "Jan";
or equivalent programming. You can assign the pointer; you cannot assign a character array.
The code depends, of course, on your platform O/S. On UNIX, you can take advantage of the system *find* command to search for a wildcard-spec filename. On Windows, you could use the DOS find command, but it can't take wild cards (and is incredibly klunky to boot). Your best bet there is to...