Imports System
Imports System.Linq
Public Module Module1
Public Sub Main()
Dim array() As Integer = {3, 5, 9, 1, 7, 8, 1, 9, 0, 3, 9}
Dim dup = From n In array
Group By n Into Group, Count()
Where Count > 1
Select n
Order By n
Console.WriteLine(String.Join(",", dup))
End Sub
End Module
' run:
'
' 1,3,9
'