Data Types
In pseudocode, data types play an essential role in defining the kind of values that variables can store and process. Understanding data types is important for writing clear and accurate algorithms, as they determine how data is handled within a program. In this section, we will explore the different data types used in pseudocode, along with their meaning and examples, as required in the Cambridge AS Level Computer Science syllabus.
Different components used in pseudocode are explained below.
DATATYPES
| DATA TYPE |
DESCRIPTION |
EXAMPLES |
| INTEGER |
a whole number |
15, 0, 27, 155 |
| REAL |
a number contains fractional part |
3.14, 1.0, 17.5 |
| CHAR |
a single character |
'A', 'c', '5', '@' |
| STRING |
a sequence of zero or more characters |
"Computer", "exam", "abc123" |
| BOOLEAN |
logical values |
TRUE, FALSE |
| DATE |
a calendar date |
'17/10/1995', 01/12/2026 |
Declaring Variables
Examples:
1. Declare integer variables and assigning values:
DECLARE age : INTEGER
DECLARE mark : INTEGER
age ← 15
mark ← 45
2. Declare and initialise Real variable:
DECLARE percentage : REAL
percentage ← 70.5
3. Declaring a char variable to store the grades of a student:
DECLARE grade : CHAR
grade ← 'B'
4. Declaring and initialising string variable:
DECLARE place : STRING
place ← "Sydney"
5. Declaring and initialising a boolean variable:
DECLARE flag : BOOLEAN
flag ← TRUE
6. Declaring and initialising a variable of type DATE:
DECLARE date_of_birth : DATE
date_of_birth ← 15/10/2005
Example #1: Write the pseudocode to calculate the sum of 10 numbers.
DECLARE sum: INTEGER
DECLARE number: INTEGER
sum ← 0
FOR count ← 1 TO 10
OUTPUT "Enter a number: "
INPUT number
sum ← sum + number
NEXT count
OUTPUT "Sum of 10 numbers:", sum
OUTPUT:
Enter a number: 10
Enter a number: 5
Enter a number: 5
Enter a number: 30
Enter a number: 12
Enter a number: 30
Enter a number: 100
Enter a number: 2
Enter a number: 44
Enter a number: 14
Sum of 10 numbers: 252