Data Types | OCR GCSE Computer Science Revision Notes 2022

Primitive Data Types

A data type is a classification of data into groups according to the kind of data they represent
Computers use different data types to represent different types of data in a program
The basic data types include:

Data type	Used for	Example
Integer	Whole numbers	10, -5, 0
Real	Numbers with a fractional part	3.14, -2.5, 0.0
Character	Single character	'a', 'B', '6', '£'
String	Sequence of characters	"Hello world", "ABC", "@#!%"
Boolean	True or false values	True, False

It is important to choose the correct data type for a given situation to ensure accuracy and efficiency in the program
Data types can be changed within a program, this is called casting

The following Python program is used to capture a users age to determine if they are old enough to vote

In this example, on line 01, no specific data type is requested
By default the data type is stored as 'string'
On line 02, a run-time error would occur because age is stored as a string and is being compared to an integer value in the selection statement
Casting the age from a string to an integer would solve the error

Conversion	Example	Output
From Integer to Real	`int_value = 5 real_value = float(int_value)`	5.0
From Real to Integer	`real_value = 5.7 int_value = int(real_value)`	5
From String to Integer	`str_value = "10" int_value = int(str_value)`	10
From Integer to String	`int_value = 5 str_value = str(int_value)`	"5"
From Boolean to String	`bool_val = True str_val = str(bool_val)`	"True"
From String to Boolean	`str_value = "True" bool_val = bool(str_value)`	True

Customers booking a holiday can choose between half board or all inclusive and a hotel star rating between 1 and 5

A typical booking record is shown in the table:

State the most appropriate data type for the following fields [2]:

boardType
starRating

Give the name of one field that could be stored as a Boolean data type [1]

Answer

boardType	String
starRating	Integer