DEMONSTRATION
OF
SEQUENTIAL
FILES
(BASIC 2.0)
Use the following program for your first experiments with sequential files.
Comments have been added
to
help you better understand it.
150 CR$ = CHR$(13)
160 OPEN 15,8,15
170 PRINT CHR$(147):REM CLEAR
SCREEN
190 PRINT
"** WRITE A FILE **"
210 PRINT
220 OPEN 2,8,2, "@O:SEQ FILE,S,W"
230 GOSUB 500
240 PRINT"ENTER A WORD,
THEN A NUMBER"
250 PRINT"OR 'END,O' TO STOP"
260 PRINT
270 INPUT A$,B
280 PRINT#2,A$;CR$;B
290 GOSUB 500
300 IF
A$<>"END"
THEN 270
310 PRINT
320 CLOSE 2
340 PRINT
"** READ SAME FILE
BACK
**"
360 PRINT
370 OPEN 2,8,2, "O:SEQ FILE,S,R"
380 GOSUB 500
390 INPUT#2,A$,B
400
RS=ST
410 GOSUB 500
420 PRINT A$,B
430 IF
RS
= 0 THEN 390
440 IF
RS<>64
THEN
PRINT" STATUS =
";RS
450 CLOSE 2
455 CLOSE
15
460 END
480 REM
**
ERROR CHECK SIR
**
500 INPUT#15,EN,EM$,ET,ES
510 IF EN>O THEN PRINT
EN
,EM$,ET ,ES :STOP
520 RETURN
51
Make a carriage return variable
Open demo
file
with replace
Check for disk errors
Accept a string
& number
from keyboard
Write them
to
the disk
file
Until finished
Tidy up
Reopen same
file
for reading
Read next string
& number from
file
Remember
file
status
Display
file
contents
until done,
unless there's
an
error
Then quit
A Basic 3.5-only version could
replace line 500 with
500 IF DS>O THEN PRINT
DS$:STOP
and delete line 510
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