CHARACTER(LEN=3) FUNCTION label3(indx)
IMPLICIT NONE

!=================================================================
! Function to obtain a character string used to label files from an
!    integer iterator.

!CHARACTER(LEN=3) :: label3
INTEGER,INTENT(IN) :: indx

   IF (indx.lt.10)                    WRITE(label3,'("00",I1)') indx
   IF (indx.ge.10.and.indx.lt.100)    WRITE(label3,'("0",I2)') indx
   IF (indx.ge.100.and.indx.lt.1000)  WRITE(label3,'(I3)') indx
   IF (indx.ge.1000)                  WRITE(label3,'("XXX")') indx

END FUNCTION label3