10 '    FILTERS  NON-ASCII CHARACTERS FROM A FILE
20 '    USEFUL FOR CLEANING UP NULLS AND CONTROL CHARACTERS FROM A
30 '    TRANSMITTED FILE.
40 '                                       RICHARD STECK  820511
50 '
60 '
70 CLOSE
80 DEFINT A-Z
90 ON ERR GOTO 470
100 KEY OFF
110 CLS:WIDTH 80: LOCATE 12,,1
120 INPUT "   ENTER NAME OF FILE TO BE FILTERED  "; F1$
130 PRINT
140 INPUT "   ENTER DESTINATION FILE NAME        "; F2$
150 IF F1$ = F2$ THEN GOTO 110
160 PRINT: PRINT
170 PRINT TAB(10), "Source file name is: "; TAB(33); F1$
180 PRINT
190 PRINT TAB(10), "Destination file name is: ";TAB(33); F2$
200 PRINT
210 INPUT " Is that correct(Y/N/Q)?  "; ANS$
220 IF (LEFT$(ANS$,1) = "Q") OR (LEFT$(ANS$,1) = "q" )  THEN STOP
230 IF NOT ((LEFT$(ANS$,1) = "Y") OR (LEFT$(ANS$,1) = "y") ) THEN GOTO 160
240 OPEN F1$ FOR INPUT AS #1
250 OPEN F2$ FOR OUTPUT AS #2
260 '
270 WHILE NOT EOF(1)
280    LINE INPUT #1,A$
290 '
300 PRINT  A$ :  '  DISPLAY STRING
310    GOSUB 370
320    PRINT #2,A$
330 WEND
340 CLOSE 1,2
350 STOP
360 '
370 '  FILTER OUT NULLS FROM A$
380 AA$= STRING$(255," ")
390 J = 1
400 FOR I = 1 TO LEN(A$)
410 TEST = ASC(MID$(A$,I,1))
420 IF TEST < 32 AND (TEST < 7 OR TEST > 13) THEN GOTO 430 ELSE MID$(AA$,J,1) =  MID$(A$,I,1) : J = J + 1
430 NEXT I
440 A$ = LEFT$(AA$,J-1)
450 RETURN
460 '
470 PRINT : PRINT "ERROR CONDITION  "; ERR; "  IN LINE NO. "; ERL: PRINT : STOP