PROGRAM deletewat2

c	Reads output from checkwat3 and deletes the waters using the
c	residue number

	CHARACTER*103	filnam, line
	LOGICAL		flag(999)/999*.FALSE./

        WRITE (6, 1000) 'Enter PDB mnemonic:'
        READ (5, 1000) filnam
        len = length(filnam)

c	First read list of waters in native PCD

	DO WHILE (.TRUE.)
	  READ (5, 1000, end=9) line
1000	  FORMAT (a)
	  IF (line(1:6) .EQ. 'Delete') THEN
	    READ (line(11:13), 1001) n
1001	    FORMAT (i3)
	    flag(n) = .TRUE.
	  endIF
	endDO
9	CLOSE (unit=1)

c	Now handle PDB file

        OPEN (unit=1, form='FORMATTED', status='OLD', readonly,
	1       file=filnam(1:len)//'.pdb')
	OPEN (unit=2, form='FORMATTED', status='UNKNOWN', 
	1	file=filnam(1:len)//'.deletewat')

	DO WHILE (.TRUE.)
15	  READ (1, 1000, end=99) line
	  IF (line(1:4) .EQ. 'ATOM' .OR. line(1:6) .EQ. 'HETATM') THEN
	    READ (line(24:26), 1001) n
	    IF (flag(n)) goto 15
	  endIF	
          len = length(line)
	  WRITE (2, 1000) line(1:len)
	endDO

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

	end

        INTEGER FUNCTION length(line)

        CHARACTER*103   line

        DO i = 103,1,-1
          IF (line(i:i) .NE. ' ') goto 9
        endDO

9       length = i

        return
        end