Local & Global Variables (Cambridge (CIE) O Level Computer Science)

Revision Note

Written by: Robert Hampton

Reviewed by: James Woodhouse

A local variable is a variable declared within a specific scope, such as a function or a code block
Local variables are accessible only within the block in which they are defined, and their lifetime is limited to that particular block
Once the execution of the block ends, the local variable is destroyed, and its memory is released

In this python code, you can see that the localVariable (with the value 10) is declared inside of the function printValue
This means that only this function can access and change the value in the local variable
It cannot be accessed by other modules in the program

Local variables
`def printValue():` `localVariable = 10` # Defines a local variable inside the function `print("The value of the local variable is:", localVariable)` `printValue()` # Call the function

Local variables

def printValue():
localVariable = 10 # Defines a local variable inside the function
print("The value of the local variable is:", localVariable)

printValue() # Call the function

A global variable is a variable declared at the outermost level of a program.
They are declared outside any modules such as functions or procedures
Global variables have a global scope, which means they can be accessed and modified from any part of the program

In this python code, you can see that the globalVariable (with the value 10) is declared outside of the function printValue
This means that this function and any other modules can access and change the value in the global variable

Global variables
`globalVariable = 10` # Defines a global variable `def printValue():` `global globalVariable` `print("The value into the variable is:", globalVariable)` `printValue()` # Call the function

Global variables

globalVariable = 10 # Defines a global variable

def printValue():
global globalVariable
print("The value into the variable is:", globalVariable)

printValue() # Call the function

Last updated: 30 August 2024

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