Data types

Question 1

Integer

Answer 1

A number without a fraction or decimal.
Can be positive or negative.

e.g. 0, -3, 107463

Question 2

Real

Answer 2

Real numbers include all numbers that exist and their fractions and decimals

Integers are real number, but it is more efficient to declare them as integers so that less memory is needed

In OCR pseudocode, real numbers are declared as “float”

e.g.
float(“1.25”)

Question 2

Real

Answer 2

Real numbers include all numbers that exist and their fractions and decimals

Integers are real number, but it is more efficient to declare them as integers so that less memory is needed

In OCR pseudocode, real numbers are declared as “float”

e.g.
float(“1.25”)

Question 3

Boolean

Answer 3

A boolean value can only be true or false

Question 4

Character

Answer 4

A character data type can store a single letter, number, or symbol

e.g. C, 3, !

Question 5

String

Answer 5

A string can hold a lost of characters of any length.
When entered, they are enclosed in single or double quotation marks.

e.g. string = “Hello”

Question 6

Importance of data type

Answer 6

Data used by a computer is only presented as 1s and 0s

The data type is needed so that the computer knows how to interpret the binary code so it can be used correctly

Question 7

Declaring data type

Answer 7

In some programming languages the data type must be declared, e.g. int age declares that the variable age stores an integer value

In other languages, the type does not have to be declared, and is instead inferred from the first type of data stored

Question 8

Casting

Answer 8

The conversion of one data type into another

e.g.
str(integer)
int(string)
float(string)

Question 9

Identify a data type that would be suitable for the variable ‘response’ in the following situations and state why it is the most appropriate.

a) response = 10/7 [2]
b) response = input(“Please enter your name”) [2]
c) response = input(“Please enter your age in years”) [2]

Answer 9

a) real/float
It contains fractions or decimals

b) string
A person’s name consists of a sequence of characters

c) integer
It is a whole number without fractions or decimals

Question 10

State what is returned by each of the following statements:

• str(9)
• int(999)
• float(90)

[3]

Answer 10

9
999
90.0