I declare my array
Dim A(N) As Integer
When I loop from 1 To N or 0 To N-1 there's an extra value at one end or the other.
What's going on?
(Intended to be a canonical question/answer.)
Asked
Active
Viewed 181 times
0
Mark Hurd
- 10,665
- 10
- 68
- 101
-
1You will get the reasoning behind that in this: http://stackoverflow.com/questions/506207/size-of-array-in-visual-basic – Rahul Tripathi Apr 24 '15 at 06:51
1 Answers
0
In VB.NET arrays almost always* have a lower bound of 0 and are declared mentioning their upper bound, not their length.
They did change the VB.NET syntax early on to allow you to remind yourself if needed:
Dim A(0 To N) As Integer
That 0 can't be anything else (such as a 1 or a constant zero).
You can loop through all VB.NET array indexes using
For i = LBound(A) To UBound(A)
or, more simply,
For i = 0 To N
(*) You can use the .NET Framework to create arrays with other lower bounds, but you need to refer to them as Array and thus with late binding (and probably Option Strict Off).
-
3It's not strictly true that arrays in VB.Net always have a lower bound of zero, see this overload of [`Array.CreateInstance`](https://msdn.microsoft.com/en-us/library/x836773a.aspx). It's just that anyone found writing such code should never be allowed near computers again. – Damien_The_Unbeliever Apr 24 '15 at 06:53