[ OCR J277 ERL ]

Module 1: Variables & Data Types

What are Variables?

A variable is a named location in memory used to store data that can change while the program is running. In OCR ERL, you create a variable simply by assigning a value to it using the = sign.

score = 0
name = "Alice"
isGameOver = False

Exercise: Variables

Declare a variable called lives and set it to 3. Print its value.

ex1.erl

Constants

A constant is like a variable, but its value cannot change once the program is running. We use the const keyword.

const PI = 3.14
const MAX_PLAYERS = 4

Exercise: Constants

Declare a constant called VAT and set it to 0.2. Print its value.

ex2.erl

Data Types & Casting

Variables automatically take the type of the value you assign, but sometimes you need to change the type manually. This is called casting.

  • int("3") converts the string "3" to the integer 3.
  • str(42) converts the integer 42 to the string "42".
  • float("3.14") converts to a real/float number.
  • bool("True") converts to a boolean.

Exercise: Casting

Convert the string "100" to an integer and store it in score. Add 50 to it and print the result.

ex3.erl
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