This study notes covers Local vs Global within Variable Scope for GCSE Computer Science. Revise Variable Scope in 3.2 Programming for GCSE Computer Science with 18 exam-style questions and 10 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 3 of 7 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Local vs Global
| Aspect | Local Variable | Global Variable |
|---|---|---|
| Declared | Inside a subprogram | Outside all subprograms |
| Accessible | Only within that subprogram | Anywhere in the program |
| Lifetime | Created when function runs, destroyed when it ends | Exists for entire program |
| Memory | Efficient - freed when not needed | Uses memory entire time |
| Safety | Can't be accidentally changed elsewhere | Can be changed from anywhere |
Practice questions for Variable Scope
Where can a local variable be accessed?
Identify and explain the scope error in this pseudocode: function calculateTotal(price, quantity) local total = price * quantity endfunction calculateTotal(10, 5) output total
Quick recall flashcards
What is variable scope?
Where a variable can be accessed in the code
What is a global variable?
A variable declared outside all subprograms, accessible anywhere in the program