Cambridge IGCSE Computer Science · Syllabus 0478 · Programming
Local Variable
What is Local Variable?
A variable declared inside a procedure or function, available only within that routine; it cannot be read or changed from anywhere else in the program.
This definition is part of the Programming chapter in Cambridge IGCSE Computer Science.
Local Variable in context
A local variable is declared inside a procedure or function and is available only within that routine. A global variable is declared outside all routines and is available throughout the program, including inside the routines. A routine's parameters behave as local variables too. Local variables are preferred because they cannot be changed by accident from somewhere else in the program, which makes a routine easier to test on its own; too many globals make a program harder to understand, harder to test and harder to change safely.
Common mistakes with Local Variable
- M19. “A local variable can be used anywhere in the program.” TruthA local variable is declared inside a procedure or function and is available only within that routine. Elsewhere the identifier refers to nothing. AlsoTwo routines cannot see each other's locals, and a local with the same name as a global is a different store.