Common mistakes in file handling pseudocode

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Quick Questions

Shade in the A or B circle for each question.

1. Which program reads a line from a file correctly?

A OPENFILE "notes.txt" FOR READ READFILE "notes.txt", Line

B OPENFILE "notes.txt" FOR WRITE READFILE "notes.txt", Line

2. Which program uses the file at the right time?

A OPENFILE "scores.txt" FOR READ READFILE "scores.txt", Score

B READFILE "scores.txt", Score OPENFILE "scores.txt" FOR READ

3. Which program finishes its file handling properly?

A OPENFILE "log.txt" FOR WRITE WRITEFILE "log.txt", "Done"

B OPENFILE "log.txt" FOR WRITE WRITEFILE "log.txt", "Done" CLOSEFILE "log.txt"

4. Which program uses the same file identifier throughout?

A OPENFILE "names.txt" FOR READ READFILE "names.txt", Name

B OPENFILE "names.txt" FOR READ READFILE "name.txt", Name

5. A file already holds 50 high scores that must be kept. Which line is safe if you only want to read them?

A OPENFILE "scores.txt" FOR WRITE

B OPENFILE "scores.txt" FOR READ

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1OPENFILE "scores.txt" FOR WRITE READFILE "scores.txt", Score		AThe file identifier in READFILE (mark.txt) is different from the one in OPENFILE (marks.txt), so the file names do not match
2OPENFILE "names.txt" FOR WRITE WRITEFILE "names.txt", Name		BError: READFILE is used on a file opened for WRITE, so the program cannot read from it
3Every file must be opened with OPENFILE before READFILE or WRITEFILE can use it		CCLOSEFILE is missing, so the file is never closed and the data may not be saved properly
4A file should be closed with CLOSEFILE once the program has finished using it		DOPENFILE "data.txt" FOR READ READFILE "data.txt", Item
5OPENFILE "marks.txt" FOR READ READFILE "mark.txt", Mark		EWRITEFILE "log.txt", Line CLOSEFILE "log.txt"
6OPENFILE "diary.txt" FOR WRITE WRITEFILE "diary.txt", Entry // program ends		FError: the file is opened FOR WRITE, which wipes any old data in names.txt before the new data is saved

Definitions

file handling error

Fill in the Blanks

Complete each line of code by filling in the missing parts.

OPENFILE "names.txt" FOR ____ READFILE "names.txt", Name CLOSEFILE "names.txt"

________ "scores.txt" FOR READ READFILE "scores.txt", Score CLOSEFILE "scores.txt"

OPENFILE "log.txt" FOR WRITE WRITEFILE "log.txt", Message _________ "log.txt"

OPENFILE "marks.txt" FOR READ READFILE "_________", Mark CLOSEFILE "marks.txt"

// Old data is lost after this line OPENFILE "best.txt" FOR _____ WRITEFILE "best.txt", NewScore

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A OPENFILE "data.txt" FOR WRITE

B READFILE "data.txt", Line

C OUTPUT Line

D CLOSEFILE "data.txt"

Question 2

A OPENFILE "log.txt" FOR WRITE

B WRITEFILE "log.txt", "Done"

C CLOSEFILE "log.text"

Question 3

A DECLARE Name : STRING

B OPENFILE "name.txt" FOR READ

C READFILE "names.txt", Name

D CLOSEFILE "names.txt"

Question 4

A OPENFILE "marks.txt" FOR READ

B WRITEFILE "marks.txt", Mark

C CLOSEFILE "marks.txt"

Question 5

A DECLARE Pet : STRING

B // open the file here

C READFILE "pets.txt", Pet

D CLOSEFILE "pets.txt"

Answer Key

Common mistakes in file handling pseudocode

Section A: Quick Questions

A — OPENFILE "notes.txt" FOR READ READFILE "notes.txt", Line

A — OPENFILE "scores.txt" FOR READ READFILE "scores.txt", Score

B — OPENFILE "log.txt" FOR WRITE WRITEFILE "log.txt", "Done" CLOSEFILE "log.txt"

A — OPENFILE "names.txt" FOR READ READFILE "names.txt", Name

B — OPENFILE "scores.txt" FOR READ

Section B: Match the Pairs

OPENFILE "scores.txt" FOR WRITE READFILE "scores.txt", Score → Error: READFILE is used on a file opened for WRITE, so the program cannot read from it

OPENFILE "names.txt" FOR WRITE WRITEFILE "names.txt", Name → Error: the file is opened FOR WRITE, which wipes any old data in names.txt before the new data is saved

Every file must be opened with OPENFILE before READFILE or WRITEFILE can use it → OPENFILE "data.txt" FOR READ READFILE "data.txt", Item

A file should be closed with CLOSEFILE once the program has finished using it → WRITEFILE "log.txt", Line CLOSEFILE "log.txt"

OPENFILE "marks.txt" FOR READ READFILE "mark.txt", Mark → The file identifier in READFILE (mark.txt) is different from the one in OPENFILE (marks.txt), so the file names do not match

OPENFILE "diary.txt" FOR WRITE WRITEFILE "diary.txt", Entry // program ends → CLOSEFILE is missing, so the file is never closed and the data may not be saved properly

Section C: Definitions

file handling error — A mistake such as using the wrong mode, missing OPENFILE or CLOSEFILE, using different file names, or opening a file FOR WRITE and wiping its old data.

Section D: Fill in the Blanks

OPENFILE "names.txt" FOR READ
READFILE "names.txt", Name
CLOSEFILE "names.txt"

OPENFILE "scores.txt" FOR READ
READFILE "scores.txt", Score
CLOSEFILE "scores.txt"

OPENFILE "log.txt" FOR WRITE
WRITEFILE "log.txt", Message
CLOSEFILE "log.txt"

OPENFILE "marks.txt" FOR READ
READFILE "marks.txt", Mark
CLOSEFILE "marks.txt"

// Old data is lost after this line
OPENFILE "best.txt" FOR WRITE
WRITEFILE "best.txt", NewScore

Section E: Spot the Error

A — The program reads from the file, so it must be opened FOR READ. Opening it FOR WRITE would wipe the old data, and READFILE cannot be used on a file opened for WRITE.

C — The file identifier in CLOSEFILE must match the one used in OPENFILE. "log.text" is a different file, so log.txt is never closed. It should be CLOSEFILE "log.txt".

B — The file name in OPENFILE (name.txt) does not match the one in READFILE and CLOSEFILE (names.txt). All file identifiers must be identical: OPENFILE "names.txt" FOR READ.

A — WRITEFILE needs the file to be opened FOR WRITE. Opening it FOR READ is the wrong mode, so the data cannot be written. It should be OPENFILE "marks.txt" FOR WRITE.

B — The OPENFILE line is missing, so READFILE tries to use a file that has not been opened. The line should be OPENFILE "pets.txt" FOR READ.