PROGRAM rotpdb

c	Apply transformation crystallographic two-fold around y-axis
c	to PDB file

	CHARACTER*66 	line
	REAL		x(3)

	WRITE (6, 1000) 'Enter filename for input file:'
1000	FORMAT (a)
	READ (5, 1000) line
	OPEN (unit=1, status='OLD', file=line, readonly, form='FORMATTED')
	WRITE (6, 1000) 'Enter filename for output file:'
	READ (5, 1000) line
	OPEN (unit=2, status='UNKNOWN', form='FORMATTED', file=line,
	1	carriagecontrol='LIST')

c	Loop

	DO WHILE (.TRUE.)
	  READ (1, 1000, end=99) line
	  READ (line(31:54), 1001) x
1001	  FORMAT (3f8.3)
	  x(1) = -x(1)
	  x(3) = -x(3)
	  WRITE (line(31:54), 1001) x
	  line(22:22) = CHAR(ICHAR(line(22:22))+6)
	  WRITE (2, 1000) line
	endDO

99	CLOSE (unit=1)
	CLOSE (unit=2)

	end

        INTEGER FUNCTION length(line)

        CHARACTER*132   line

        DO i = 132,1,-1
          IF (line(i:i) .NE. ' ') goto 9
        endDO

9       length = i

        return
        end