Difference between ByVal and ByRef?

Question

What is the difference? I always use ByVal, but, I don\'t really have a good idea of when should I and when not...

Answer 1

ByRef, one value will have 2 addresses

So if x=80 (80 is value and x is address, then for example variable y can be 80 as well, and thus 80 can be accessed by x and y)