Commodore 1541-II - Demonstration of Sequential Files

DEMONSTRATION OF SEQUENTIAL FILES
Use the following program for your
Comments have been added to help you
150CR$ = 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,"@0:SEQ FILE,S,W"
230 GOSUB 500
240 PRINT'ENTER A WORD,
THEN A NUMBER1*
250 PRINT"OR 4END,0' TO STOP*'
260 PRINT
270 INPUT A$,B
280 PRINT#2,A$;CR$;B
290 GOSUB 500
300 IF A$O"END" THEN 270
310 PRINT
320 CLOSE 2
340 PRINT "** READ SAME FILE
BACK **"
360 PRINT
370 OPEN 2,8,2,"0:SEQ FILE,S,R"
380 GOSUB 500
390 INPUT#2,A$,B
400RS = ST
410 GOSUB 500
420 PRINT A$,B
430 IF RS = 0 THEN 390
440 IF RSO64 THEN
PRINTt4STATUS = ";RS
450 CLOSE 2
460 END
480 REM ** ERROR CHECK S/R **
500 INPUT#15,EN,EM$,ET,ES
510 IF EN>0 THEN PRINT
EN,EM$,ET,ES:STOP
520 RETURN
first experiments with sequential files.
better understand it.
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>0 THEN PRINT
DS$:STOP
and delete line 510
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