Scope

Scope refers to where a variable is visible and accessible in your code.

Global Variables

Variables declared outside any function or subroutine are global — they are accessible from anywhere in the program, including inside functions:

  score = 0           ' global variable

Sub AddPoints(n)
    score = score + n    ' can read and write the global
End Sub

AddPoints(10)
Print score             ' → 10

Local Variables

Variables declared inside a function or subroutine with Dim are local — they exist only while that function is executing and are invisible outside it:

  Sub MyFunc()
    Dim temp
    temp = 42
    Print temp          ' → 42
End Sub

MyFunc()
' Print temp   ← would cause an error; temp doesn't exist here

Best Practices

Prefer local variables for intermediate calculations to avoid accidental name collisions.
Use global variables sparingly — typically for game state (score, lives, level) that many parts of your code need to read.