Type check

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. A user types 'abc' into an age field that must be a whole number. Which check should reject it?

A Type check

B Presence check

2. Which statement describes a type check correctly?

A It checks the input is the expected data type, such as INTEGER

B It checks the input is typed in twice and matches

3. A program expects the age 15. Which input would a type check for INTEGER reject?

A 15

B fifteen

4. Which data type should an age field be checked against?

A STRING

B INTEGER

5. A type check on an age field accepts 200. Is this statement true or false?

A True, a type check only tests the data type, and 200 is a whole number

B False, a type check always rejects numbers that are too big

Match the Pairs

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

Left column		Right column
1Age must be an INTEGER		AA type check: the input must be a number that can have a decimal part, so text is rejected
2Price must be a REAL number		BA type check: the input must be a whole number, so letters like "ten" are rejected
3A type check rejects letters when a whole number is expected, such as an age		CThe input must be of type INTEGER
4In the exam, a type check is described in words, linked to a data type		DA STRING can hold letters, so it will not enforce whole numbers. The type check should require an INTEGER.
5Type check: Age must be between 0 and 120		EThis describes a range check, not a type check. A type check tests the data type, for example that Age is an INTEGER.
6Age is stored as STRING so a type check will make sure it is a whole number		FIF Age is not an INTEGER THEN OUTPUT "Enter a whole number"

Definitions

type check

Fill in the Blanks

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

// Type check: expects a whole number DECLARE Age : _______

DECLARE Age : INTEGER DECLARE Name : ______

_______ Age : INTEGER INPUT Age

DECLARE Age : INTEGER OUTPUT "Enter your age" _____ Age

// Type check: Age must be INTEGER DECLARE ___ : INTEGER

Spot the Error

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

Question 1

A DECLARE Age : INTEGER

B OUTPUT "Enter your age"

C OUTPUT Age

D OUTPUT "Age accepted"

Question 2

A DECLARE Age : STRING

B INPUT Age

C OUTPUT Age + 1

Question 3

A // Type check: Age must be STRING

B DECLARE Age : INTEGER

C INPUT Age

Question 4

A DECLARE Age : INTEGER

B DECLARE Name : STRING

C INPUT Name

D INPUT Age : INTEGER

Question 5

A DECLARE Age : INTEGER

B INPUT "Age"

C OUTPUT "Valid age: ", Age

Answer Key

Type check

Section A: Quick Questions

A — Type check

A — It checks the input is the expected data type, such as INTEGER

B — fifteen

B — INTEGER

A — True, a type check only tests the data type, and 200 is a whole number

Section B: Match the Pairs

Age must be an INTEGER → A type check: the input must be a whole number, so letters like "ten" are rejected

Price must be a REAL number → A type check: the input must be a number that can have a decimal part, so text is rejected

A type check rejects letters when a whole number is expected, such as an age → IF Age is not an INTEGER THEN OUTPUT "Enter a whole number"

In the exam, a type check is described in words, linked to a data type → The input must be of type INTEGER

Type check: Age must be between 0 and 120 → This describes a range check, not a type check. A type check tests the data type, for example that Age is an INTEGER.

Age is stored as STRING so a type check will make sure it is a whole number → A STRING can hold letters, so it will not enforce whole numbers. The type check should require an INTEGER.

Section C: Definitions

type check — A validation check that tests an input is the expected data type, such as a whole number (INTEGER) for an age, and rejects letters or other wrong types.

Section D: Fill in the Blanks

// Type check: expects a whole number
DECLARE Age : INTEGER

DECLARE Age : INTEGER
DECLARE Name : STRING

DECLARE Age : INTEGER
INPUT Age

DECLARE Age : INTEGER
OUTPUT "Enter your age"
INPUT Age

// Type check: Age must be INTEGER
DECLARE Age : INTEGER

Section E: Spot the Error

C — The program must read the age with INPUT Age so the value can be checked as an INTEGER. OUTPUT only displays a value and does not read one.

A — An age is a whole number, so the type check expects INTEGER. Declaring Age as STRING would accept letters and break the arithmetic. It should be DECLARE Age : INTEGER.

A — A type check on an age tests that the input is a whole number (INTEGER). It does not expect STRING, so the comment should say INTEGER.

D — The data type is set in the DECLARE statement, not in INPUT. The line should be just INPUT Age. The type check then compares the input with the declared INTEGER type.

B — Quotes make Age a piece of text, so the input would not be stored in the INTEGER variable. It should be INPUT Age with no quotes.