So ich hab jetzt mal versucht den Code aufzustellen. Leider klappt es noch nicht ganz. Vielleicht sieht jemand den Fehler.

Vielen Dank fuer eure Hilfe!

Viele Gruesse
Nici

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Option Explicit


Function Profit(ByVal Ini_Money As Long, ByVal Max_Plays As Long, Stop_Profit As Long) As Long

Dim i As Long, b As Long, p As Long, tp As Long, r As Double, rd As Long ' i,b,p,tp,rd as long as these must be integer values

 ' i is the money invested in each round
 ' b number of bets
 ' p profit obtained in one bet/round
 ' tp total profit obtained with all bets/rounds
 ' r is a random number
 ' rd is either 0 or 1 depending on the value of r; we set 1= colour picked 0=other colour
 
i = 1 ' every game starts with an initial investment of 1$
b = 1 ' the game starts with b=1 meaning that it represents the first bet/round
tp = 0 ' total profit at the start of the game

Do While Ini_Money >= i And b <= Max_Plays And tp <= Stop_Profit

r = Rnd() 'the rnd function gives a random number between 0 and 1
If r >= 0.513513513513513 Then
rd = 1
Else
rd = 0
End If

p = 2 * i * rd 'the profit we obtain during one bet is either 2$ in case our colour wins or 0$ if our colour looses
 
  If rd = 0 Then
  Ini_Money = Ini_Money - i 'if we loose our initial money decreases by the investment made in this round
  i = i * 2
                'in case we loose we have to invest the double amount of money in the next round
 Else 'there is only one other case which will be rd=1 meaning that our colour wins. In this case the following applies:
  Ini_Money = Ini_Money + p 'if we win our initial money increases by the profit made in this round
  i = 1 'if we win we will continue to invest 1$ for the next round
End If

If i > Ini_Money Then
 WorksheetFunction.Sum (i) - Ini_Money
 End If
 
b = b + 1 'the cumulative number of bets is obtained by adding 1 after each bet(one further bet)
 
tp = tp + p ' the total profit will be the cumulative profit of all previous bets plus the profit obtained the current bet
Loop

 Profit = tp
 
End Function