SUBROUTINE NBLANK (A, IFLAG, NBLK)

*** Return position of last non-blank in string (IFLAG = 2)
*** or position of first non-blank in string (IFLAG = 1)

      IMPLICIT DOUBLE PRECISION (A-H, O-Z)
      IMPLICIT INTEGER (I-N)
*     IMPLICIT UNDEFINED (A-Z)

      INTEGER IFLAG, NBLK, LENG, IBLK
      CHARACTER*(*) A

      LENG = LEN(A)

      IF (IFLAG .EQ. 2) THEN
        DO 1 IBLK = LENG, 1, -1
          IF ( A(IBLK:IBLK) .NE. ' ' ) THEN
            NBLK = IBLK
            RETURN
          ENDIF
    1   CONTINUE
      ELSEIF (IFLAG .EQ. 1) THEN
        DO 2 IBLK = 1, LENG, +1
          IF ( A(IBLK:IBLK) .NE. ' ' ) THEN
            NBLK = IBLK
            RETURN
          ENDIF
    2   CONTINUE
      ENDIF

* String contains all blanks

      NBLK = 0

      RETURN
      END