Local & Global Variables (Cambridge International IGCSE Computer Science)

Local Variables

Spec point — (c) Understand and use local and global variables

What is a local variable?

• 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

Examples

• In this 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

Global Variables

Spec point — (c) Understand and use local and global variables

What is a global variable?

• 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

Examples

• In this 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