C     @(#)cdigit.f	1.1     02/19/98
C
      logical function cdigit (a)

c returns .TRUE. if all characters in string are digits, else .FALSE.

      character*(*) a

      cdigit = .false.
      do i = 1, len(a)
        if (a(i:i) .lt. '0' .or. a(i:i) .gt. '9') return
      end do
      cdigit = .true.
      return
      end