Computer programs use data types to store and process different types of data. This document defines and provides examples of common data types including integers, reals, strings, Booleans, one-dimensional arrays, and records. Integers store whole numbers, reals store decimal numbers, strings store alphanumeric text, Booleans store true/false values, arrays store multiple elements of the same type indexed by number, and records store grouped data of different types.

1. Data Types

2. Data Types
Computer programs need to process and store data
Programming languages define different data types to
store different types of data
We are interested in the following data types:
Integer, Real, String, Boolean, One-Dimensional Arrays
and Records

3. Integer
 An integer data type is used to store a whole number
 An integer can be positive or negative and includes 0
 e.g. 4, 1025, -27, 0, -911, 1

4. Real
 A real data type is used to store a decimal number
 A real can be positive or negative and includes 0
 e.g. 22.1, -13.775, 0.00, -5.15, 102.4258

5. String
 A string data type is used to represent alphanumeric
data (i.e. text)
 e.g. "Hello World", "0131 334 9262",
"How are you today?", "ABC-DEF-%£$-123"
 Most programming languages provide ways to
manipulate strings
e.g. get the string length, get the first character, get the
4th-6th characters, find the first space

6. Boolean
 A boolean data type can only represent 2 values: true
or false.
 Depending on the programming language true can also
be a 1 or yes, while false can be a 0 or no

7. One Dimensional Arrays
 An array is a series of objects all of which are the same type
 Each object in an array is called an array element
 The index of the first array element is normally zero
 Arrays are useful in programming because they can be used
with a loop
(eg count occurrences, linear search, find max/min)

8. One Dimensional Arrays
An example array of integers: The winning lottery balls
Uses:
Write a program to loop through checking a user’s
lottery numbers

9. One Dimensional Arrays
An example array of reals: Daily temperatures over a week
Uses:
Write a program to calculate the average daily
temperature in a week

10. One Dimensional Arrays
An example array of Strings: Pupil names
Uses:
Write a program to sort pupils into alphabetical order

11. Record
A record can be used to store variables of different data
types.
This pseudocode shows how to declare a record
structure.

12. Array of Records
In order to store multiple records, it is useful to use an
array.
This pseudocode shows how to declare an array of 20
records of data type UserRecord.

13. Array of Records
The following pseudocode shows how to loop through an
array of records, accessing individual fields.