Implementation: Data types and structuresStoring numbers

Integers

The following code is used to create an INTEGER variable that will be used to store an age.

DECLARE age AS INTEGER INITIALLY 0

SEND “Enter your age” TO DISPLAY

RECEIVE age FROM KEYBOARD

The user is asked to enter their age and when they type in a number, the value is stored in the 'age' variable.

An integer is a whole number - a number without decimal places.

Integers can be positive or negative.

Examples of integers:

• 24
• -36
• 4303
• -89730
• 7903493
• 0

This program will only accept a whole number. Anything else will cause an error. Here's that line of code running:

When the number 45 is entered the program works fine. However, here's the same line of code running with something different entered:

Here the user entered the word 'old' when they were asked for their age. The program was expecting an integer (a whole number) and therefore shows an error.

To store a whole number, use the data type known as an 'integer'.

Real numbers

Numbers that contain a decimal point are stored in a data type called REAL.

Variables that use the real data type can accept both positive and negative numbers with a decimal place.