Poisson Data by Long Method - UDF Error?

[Juggler_IN]

I am trying to convert a C language code to VBA. The converted VBA UDF code is:

Public Function Poisson2( _
       Optional ByVal C As Double = 4) As Long
    
    If C <= 0# Then Exit Function


    Dim d As Double, beta As Double, alpha As Double, k As Double, u As Double, v As Double, x As Double, n As Long, y As Double
    Dim temp As Double, lhs As Double, rhs As Double
    d = 0.767 - 3.36 / C
    beta = Application.WorksheetFunction.pi / Sqr(3# * C)
    alpha = beta * C
    k = Log(Abs(d)) - C - Log(beta)


x1:
    u = Rnd()
    x = (alpha - Log((1# - u) / u)) / beta
    n = Int(x + 0.5) - 1 * (Int(x + 0.5) > (x + 0.5))    ' Application.WorksheetFunction.Floor(x + 0.5,1)
    If (n < 0) Then
        v = Rnd()
        y = alpha - beta * x
        temp = 1# + Exp(y)
        lhs = y + Log(v / (temp * temp))
        rhs = k + n * Log(C) - Log(Apllication.Worksheetfunction.Fact(n))
        If (lhs <= rhs) Then
            Poisson2 = n
        Else
        GoTo x1
        End If
    GoTo x1
    End If


End Function

And, I am referencing the C code from:

https://www.johndcook.com/SimpleRNG.cpp

and the reference code is:

[COLOR=#000000]int SimpleRNG::PoissonLarge(double lambda)
[/COLOR]

I have tried an exact replication but my UDF is not giving adequate output and I need help for the same.