stack overflow exception in quicksort - vb.net

Question

I am trying to make a quick sort however i am having trouble with a stack overflow exception in VB.net.
The sort works correctly when x = 3, intermittently when x = 5 and on one occasion sorted half of the list when x = 10.
Please advise, thanks
Dim x As Integer = 10
Dim numArrray(x - 1) As Integer
For i = 0 To x - 1
Randomize()
numArrray(i) = CInt(Rnd() * 9)
Next
Quicksort(numArrray, 0, numArrray.Length - 1)
For i = 0 To x - 1
Console.Write(numArrray(i))
Next
Console.ReadLine()
End Sub
Sub Quicksort(ByVal array() As Integer, ByVal min As Integer, ByVal max As Integer)
Dim pivot As Integer
If min < max Then
pivot = partition(array, min, max)
Quicksort(array, min, pivot - 1)
Quicksort(array, pivot + 1, max)
End If
End Sub
Function partition(ByVal array() As Integer, ByVal min As Integer, ByVal max As Integer) As Integer
Dim pivot As Integer = array(max)
Dim count As Integer = min - 1
Dim placeholder As Integer
For i = min To max - 1
If array(i) < pivot Then
count += 1
placeholder = array(count)
array(count) = array(i)
array(i) = placeholder
End If
Next
If array(max) < array(count + 1) Then
placeholder = array(count + 1)
array(count + 1) = array(max)
array(max) = placeholder
End If
Return count
End Function

Answer 1

Since its a stack overflow it will be in the nested calls to Quicksort, looking at partition I think you have a bounds error, as per this version of the algorithm en.wikipedia.org/wiki/Quicksort you should return count + 1 from partition, on your current implementation count can start below min and stay that way which would be an infinite regression as your nested call would have the same inputs (ie if you return count = min - 1 then you do a recursive call back to Quicksort(array, pivot + 1, max) == Quicksort(array, min, max)