// do something here

Module Module1
 
    Sub Main()
 
        Dim i, j, ctr As Integer
        Dim doorSwitch As String = "?"
        Dim smartMonty As String = "?"
        Dim prizeDoor(3) As Boolean
        Dim rand As Random = New Random()
        Dim doorMontyOpens As Integer
        Dim doorYouOpen As Integer
        Dim carsWon As Integer = 0
 
        Console.WriteLine("The Monty Hall Problem")
        Console.Write("How many times to run the simulation? ")
        ctr = Val(Console.ReadLine())
        If ctr < 1 Then End
 
        Console.Write("Are you going to switch doors? [Y/N/M] ")
        While Not "YNM".Contains(doorSwitch)
            doorSwitch = Console.ReadKey.KeyChar.ToString.ToUpper
        End While
        Console.WriteLine()
 
        Console.Write("Does Monty know where the car is? [Y/N/M] ")
        While Not "YNM".Contains(smartMonty)
            smartMonty = Console.ReadKey.KeyChar.ToString.ToUpper
        End While
        Console.WriteLine()
 
        For i = 1 To ctr
 
            ' set up the prize doors
            For j = 1 To 3
                prizeDoor(j) = False
            Next
            prizeDoor(rand.Next(1, 4)) = True
 
            Console.Write(i.ToString() + " (")
            For j = 1 To 3
                Console.Write(If(prizeDoor(j), "$", j.ToString))
            Next
            Console.Write(") -- ")
 
            ' Monty shows you a door
            If smartMonty = "Y" Or (smartMonty = "M" And _
                                    rand.NextDouble > 0.5) Then
                doorMontyOpens = If(prizeDoor(2), 3, 2)
            Else
                doorMontyOpens = rand.Next(2, 4)
                If prizeDoor(doorMontyOpens) Then
                    carsWon = carsWon + 1
                    Console.WriteLine("Monty revealed the car!!!!!")
                    Continue For
                End If
            End If
            Console.Write("Monty reveals a goat behind door #" + _
                          doorMontyOpens.ToString + " -- ")
 
            ' pick a door to open
            If doorSwitch = "Y" Or (doorSwitch = "M" And _
                                  rand.NextDouble > 0.5) Then
                doorYouOpen = If(doorMontyOpens = 2, 3, 2)
                Console.Write("You switched to door #" + _
                              doorYouOpen.ToString + " -- ")
            Else
                doorYouOpen = 1
                Console.Write("You stayed with door #1 -- ")
            End If
 
            ' did we win?
            If prizeDoor(doorYouOpen) Then
                Console.WriteLine("You won the car!!!!!")
                carsWon = carsWon + 1
            Else
                Console.WriteLine("You won the goat.")
            End If
 
        Next
 
        Console.WriteLine(" ")
        Console.WriteLine("You won the car " + carsWon.ToString + _
                          " times out of " + ctr.ToString)
        Console.WriteLine("Winning percentage: " + (carsWon * _
                            100.0 / ctr).ToString("##0.0"))
        Console.WriteLine(" ")
        Console.WriteLine("Strike any key to end...")
        Console.ReadKey()
 
    End Sub
 
End Module