infinite loop?

i'm programing a blackjack game, it works fine except the sub for preventing a vard from reapearing. if i run it vb says stackoverflow, and that there might me an infinite loop. here is the cood of the control does anyone see if it is an infinite loop or not?

Code:

---

Public Class card

  Private getal As Random = New Random

  Private card As String
  Private Valuecard As Integer
  Private cardgetal As Integer
  Protected cards_used As ArrayList = New ArrayList
  Private card_array() As String = {"h1", "k1", "r1", "s1", _
                                    "h2", "k2", "r2", "s2", _
                                    "h3", "k3", "r3", "s3", _
                                    "h4", "k4", "r4", "s4", _
                                    "h5", "k5", "r5", "s5", _
                                    "h6", "k6", "r6", "s6", _
                                    "h7", "k7", "r7", "s7", _
                                    "h8", "k8", "r8", "s8", _
                                    "h9", "k9", "r9", "s9", _
                                    "h10", "k10", "r10", "s10", _
                                    "hv", "kv", "rv", "sv", _
                                    "hq", "kq", "rq", "sq", _
                                    "hh", "kh", "rh", "sh"}

  Protected Function genereerKaart() As String

    cardgetal = getal.Next(0, 51)
    card = card_array(cardgetal)
    controle_card(card)
    Return card

  End Function
  Private Sub controle_card(ByVal card As String)
    Dim i = 0

    If cards_used.Count = 0 Then
      cards_used.Add(card)
    Else

      Do Until i = (cards_used.Count)
        If card IsNot cards_used(i) Then
          i = i + 1
        Else
          genereerKaart()
          Stop
        End If

      Loop

      cards_used.Add(card)
    End If
  End Sub
end class

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In the controle_card sub you call genereerKaart functions which in tunr calls controle_card

Code:

---

    controle_card
    -> genereerKaart
      -> controle_card
          -> genereerKaart
            -> controle_card
....

---

stack overflow as a result

any ideas how to fix it?

Try this:

Code:

---

Protected Function genereerKaart() As String
    Do
        cardgetal = getal.Next(0, 51)
        card = card_array(cardgetal)
    Loop Until controle_card(card)
    Return card
End Function


Private Function controle_card(ByVal card As String) As Boolean
   
  If Not cards_used.Contains(card) OrElse cards_used.Count = 0 Then
        cards_used.Add(card)
        Return True
    Else
        Return False
    End If
   
End Function

---

jeah its working knwo thank you