g77 treats double-quote (`"')
as beginning an octal constant of
when the -fvxt option is specified.
The form of this octal constant is
where octal-digits is a nonempty string of characters in the set `01234567'.
For example, the -fvxt option permits this:
PRINT *, "20 END
The above program would print the value `16'.
See Integer Type, for information on the preferred construct for integer constants specified using GNU Fortran's octal notation.
(In the GNU Fortran language, the double-quote character (`"') delimits a character constant just as does apostrophe (`''). There is no way to allow both constructs in the general case, since statements like `PRINT *,"2000 !comment?"' would be ambiguous.)