This document discusses sequential access files in BASIC programming. It covers opening, writing, reading, appending, and closing sequential files using statements like OPEN, WRITE#, PRINT#, INPUT#, LINE INPUT#, CLOSE, and INPUT$. It also mentions other file handling statements like FILES, CHDIR, MKDIR, RMDIR, NAME, KILL, SHELL and SYSTEM. The document provides details on using different modes in OPEN statements, and using WRITE#, PRINT#, INPUT# and LINE INPUT# statements to write, read and input data from sequential files.

3. ▪ Program File
▪ Data File

4. ▪ Sequential Access Files
▪ Random Access Files

5. Start Open Read/Write Close Stop

6. ➢ To open a sequential data file, OPEN Statement is used

7. Mode Purpose
OUTPUT
To create a new data file and write data in it. It starts writing data
always from the beginning of the file (BOF).
INPUT To retrieve the contents of the existing data file.
APPEND
To add more records in the existing file. It starts adding of data always
from the end of the file (EOF).
Mode If File exists If File does not exists
OUTPUT Creates a new file Creates a new file
INPUT Opens the existing file
Error Message
"File not found"
APPEND Opens the existing file Creates a new file

8. OPEN “STUDENT.DAT” FOR OUTPUT AS #1
OPEN “D:MARKS.DAT” FOR INPUT AS #2

9. OPEN “MARKS.DAT” FOR APPEND AS #3
OPEN “STAFF.DAT” FOR INPUT AS #1

10. OPEN “MODE”, #FILENUMBER, “FILENAME”

11. ➢ To close one or more opened sequential data file, CLOSE Statement is used

12. ➢ Continuation……

13. ➢ To write data in a new sequential data file, follow the given instructions

14. ➢ continuation
WRITE#
WRITE[# FILENUMBER], LIST OFVARIABLES
PRINT#
PRINT[# FILENUMBER], LIST OFVARIABLES

15. ➢ continuation
WRITE# PRINT#
a. WRITE# inserts commas between the data items.
a. PRINT# statements adds spaces between data
items while storing data.
b. It encloses string in double quotation marks. b. It does not enclose strings in any quotation.
c. WRITE# statements stores values to a file as a
separated data item so data in a row can be read
individually.
c. PRINT# statement writes values to a file as a single
data, so data in a row can’t be read individually.

16. ➢ To read data of a sequential data file, follow the given instructions

17. ➢ Continuation……….
INPUT# Statement
INPUT # FILENUMBER, LIST OFVARIABLES
INPUT # 1, Naam$, Address$, Age

18. ➢ Continuation……….
LINE INPUT# Statement
LINE INPUT # FILENUMBER,VARIABLE$
Note:The data to be read from a data file must be matched with the list of variables.

19. EOF (FILENUMBER)

26. ➢ To add data in the existing sequential data file, follow the given instructions

28. INPUT$ Function

29. FILES Statement

30. CHDIR Statement

31. MKDIR Statement
RMDIR Statement

32. NAME … AS Statement

33. KILLStatement

34. SHELLStatement

35. SYSTEMStatement

36. To update data or record of a sequential data file, follow these task