Declaring a variable to hold file data

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Quick Questions

Shade in the A or B circle for each question.

1. Which line correctly declares a variable to hold a line of text read from a file?

A DECLARE LineOfText STRING =

B DECLARE LineOfText : STRING

2. Which line correctly declares a variable to hold a whole number, such as a score, that will be written to a file?

A DECLARE Score : INTEGER

B DECLARE Score : STRING

3. When should DECLARE LineOfText : STRING appear in the program?

A Before the READFILE command that stores a line in LineOfText

B After the READFILE command that stores a line in LineOfText

4. Which identifier is the more meaningful choice for a variable that holds a line of text read from a file?

A LineOfText

B x

5. What does DECLARE do in a file handling program?

A It opens the file so that data can be read from it

B It creates a variable that can hold data read from or written to a file

Match the Pairs

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

Left column		Right column
1DECLARE LineOfText : STRING		AThe colon is missing between the identifier and the data type. It should be DECLARE LineOfText : STRING.
2DECLARE Score : INTEGER		BDECLARE PlayerName : STRING
3Declare the variable first, then use it to store a line read from the file		CCreates a variable called LineOfText that can hold a line of text read from or written to a file
4Give the variable a meaningful name and the correct data type for the file data		DCreates a variable called Score that can hold a whole number, such as a value read from a file
5READFILE "Notes.txt", LineOfText DECLARE LineOfText : STRING		EThe variable is declared after READFILE uses it. DECLARE must come before the file command that uses the variable.
6DECLARE LineOfText STRING		FDECLARE LineOfText : STRING READFILE "Notes.txt", LineOfText

Definitions

DECLARE LineOfText : STRING

Fill in the Blanks

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

_______ LineOfText : STRING

DECLARE LineOfText : ______

DECLARE Score : _______

DECLARE LineOfText : STRING OPENFILE "Notes.txt" FOR READ READFILE "Notes.txt", __________

DECLARE _____ : INTEGER OPENFILE "Scores.txt" FOR WRITE WRITEFILE "Scores.txt", Score

Spot the Error

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

Question 1

A DECLARE LineOfText STRING

B OPENFILE "notes.txt" FOR READ

C READFILE "notes.txt", LineOfText

D CLOSEFILE "notes.txt"

Question 2

A DECLARE Score : INTEGER

B DECLARE LineOfText = STRING

C OPENFILE "data.txt" FOR READ

D READFILE "data.txt", LineOfText

Question 3

A DECLARE LineOfText : STRING

B OPENFILE "log.txt" FOR READ

C READFILE "log.txt", LineText

D CLOSEFILE "log.txt"

Question 4

A DECLARE Score : INTEGER

B Score ← 50

C OPENFILE "score.txt" FOR WRTE

D WRITEFILE "score.txt", Score

E CLOSEFILE "score.txt"

Question 5

A DECLARE Name : STRING

B DECLARE Score : INTEGER

C Score ← "ten"

D Name ← "Ava"

Answer Key

Declaring a variable to hold file data

Section A: Quick Questions

B — DECLARE LineOfText : STRING

A — DECLARE Score : INTEGER

A — Before the READFILE command that stores a line in LineOfText

A — LineOfText

B — It creates a variable that can hold data read from or written to a file

Section B: Match the Pairs

DECLARE LineOfText : STRING → Creates a variable called LineOfText that can hold a line of text read from or written to a file

DECLARE Score : INTEGER → Creates a variable called Score that can hold a whole number, such as a value read from a file

Declare the variable first, then use it to store a line read from the file → DECLARE LineOfText : STRING READFILE "Notes.txt", LineOfText

Give the variable a meaningful name and the correct data type for the file data → DECLARE PlayerName : STRING

READFILE "Notes.txt", LineOfText DECLARE LineOfText : STRING → The variable is declared after READFILE uses it. DECLARE must come before the file command that uses the variable.

DECLARE LineOfText STRING → The colon is missing between the identifier and the data type. It should be DECLARE LineOfText : STRING.

Section C: Definitions

DECLARE LineOfText : STRING — Creates a variable named LineOfText that holds text. Declare it before the file commands that use it, for example before READFILE stores a line in it.

Section D: Fill in the Blanks

DECLARE LineOfText : STRING

DECLARE Score : INTEGER

DECLARE LineOfText : STRING
OPENFILE "Notes.txt" FOR READ
READFILE "Notes.txt", LineOfText

DECLARE Score : INTEGER
OPENFILE "Scores.txt" FOR WRITE
WRITEFILE "Scores.txt", Score

Section E: Spot the Error

A — The colon is missing. A declaration needs the form DECLARE <identifier> : <data type>, so it should be DECLARE LineOfText : STRING.

B — A declaration uses a colon between the identifier and the data type, not an equals sign. It should be DECLARE LineOfText : STRING.

C — LineText was never declared. The variable that READFILE stores the data in must be the declared one, so it should be READFILE "log.txt", LineOfText.

C — WRTE is a spelling mistake. The file mode must be spelled WRITE, so it should be OPENFILE "score.txt" FOR WRITE.

C — Score was declared as INTEGER, so it cannot hold text. It should be assigned a whole number, such as Score ← 10.