Data Types & Casting (AQA GCSE Computer Science)

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Data Types & Casting

What is a data type?

  • 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 or String handling operations

  • You can read more about string handling operations and converting data types here

Worked Example

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:

firstName

Jacob

lastName

Franks

boardType

All inclusive

starRating

5

bookingComplete

True

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

A simple two-row table with blue headers labeled "boardType" and "starRating" and empty cells beneath.

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

Answer

Table with two rows and two columns. First column has "boardType" and "starRating" in blue cells, second column has "String" and "Integer" in green cells.
  • bookingComplete

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