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]:
| boardType | |
| starRating |
Give the name of one field that could be stored as a Boolean data type [1]
Answer
| boardType | String |
| starRating | Integer |
- bookingComplete
