C COORDSCAN.F - FOR LOOKING FOR NULL COORDINATE VALUES IN
C THE MIDDLE OF LINES OF DATA
C
      INTEGER*4 LINE,LINEOLD,VALID
      CHARACTER*1 COORD
      LOGICAL GOOD
C
      OPEN(UNIT=3,FILE='queens.ldt',READONLY)
      OPEN(UNIT=4,FILE='error')
      LINEOLD=0
      VALID=0
      GOOD=.FALSE.
C
   10 READ(3,100,END=20) LINE,COORD
  100 FORMAT(I6,41X,A1)
      IF (LINE .NE. LINEOLD) THEN
      IF (VALID .GT. 1) THEN
      WRITE(4,200) LINEOLD,VALID
  200 FORMAT(' LINE',I6,' HAS ',I4,' VALID SEGMENTS')
      ENDIF
      LINEOLD=LINE
      VALID=0
      GOOD=.FALSE.
      ENDIF
C
C
      IF (COORD .NE. '9' .AND. .NOT. GOOD) THEN
C GOOD DATA
      GOOD=.TRUE.
      VALID=VALID+1
      ENDIF
C
C
      IF (COORD .EQ. '9') THEN
      GOOD=.FALSE.
      ENDIF
C
C
      GOTO 10
C
C
   20 CONTINUE
      STOP
      END