I dont know why 'Doub' isn't updating - vb.net

Question

I'm working on a program to count every time the dice
roll a double but my variable I'm trying to add to the listbox isn't updating and I don't know why.
Here's the code:
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'declare vars
Dim teal, red, doub As Integer
Dim rand As New Random
teal = rand.Next(6)
red = rand.Next(6)
#Region "Clear"
Irrelevant stuff
#End Region
'green dice
irrelevant if statement
'red dice
irrelevant if statement
'doubles
**If red = teal Then
doub = doub + 1
output.Items.Clear()
output.Items.Add("Doubles: " & doub)
End If**
End Sub
End Class
In the if statements about the dice part
there is nothing to influence the 'doub' variable
so thats why i put "irrelevant if statement"
also because stackoverflow said the post was mostly code

Answer 1

Your doub variable is declared inside the button click handler so its scope is only within that procedure. That means it's getting released after every click. You need to have it outside your button click handler:
Dim doub As Integer
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
' Declare variables
Dim teal As Integer
Dim red As Integer
Dim rand As New Random
teal = rand.Next(6)
red = rand.Next(6)
Debug.Print(teal & "-" & red)
' Doubles
If red = teal Then
doub += 1
Debug.Print("Doubles: " & doub)
End If
End Sub
You can learn about variable scope in this link: How to: Control the Scope of a Variable
Output (got a double on first try!):
4-4
Doubles: 1
1-5
0-5
5-0
2-2
Doubles: 2
3-0
This quick test shows another problem in your code: you can roll 0, 1, 2, 3, 4, 5 and 6. You should use rand.Next(1,6) instead, assuming you are trying to simulate a dice throw.