! Subroutine to convert lowercase ASCII characters in a string
! to uppercase.  Generalizing this to multinational character sets
! requires a significant effort.
!
! This is just one of many possible implementations.  For example, one
! might use a table indexed by the character value, this could be written
! as a function or as a subroutine with an optional output argument, etc.
!
subroutine UPCASE (STRING)
implicit none
character (len=*),INTENT(INOUT) :: STRING
integer I
character(len=1) C

do I = 1,LEN(STRING)
  C = STRING(I:I)
  if ((C >= 'a') .and. (C <= 'z')) then
    STRING(I:I) = CHAR(ICHAR(C)-32)
    end if
  end do
return
end subroutine UPCASE

! Subroutine to convert uppercase ASCII characters in a string
! to lowercase.  Generalizing this to multinational character sets
! requires a significant effort.
!
! This is just one of many possible implementations.  For example, one
! might use a table indexed by the character value, this could be written
! as a function or as a subroutine with an optional output argument, etc.
!
subroutine DOWNCASE (STRING)
implicit none
character (len=*),INTENT(INOUT) :: STRING
integer I
character(len=1) C

do I = 1,LEN(STRING)
  C = STRING(I:I)
  if ((C >= 'A') .and. (C <= 'Z')) then
    STRING(I:I) = CHAR(ICHAR(C)+32)
    end if
  end do
return
end subroutine DOWNCASE