Option Explicit

Private Sub cmdCalc_Click()

Dim n As Integer, p As Integer

n = Abs(Val(txtN.Text))

p = Abs(Val(txtP.Text))

If n > 0 And p > 0 And n >= p Then

txtComb.Text = fact(n) / fact(n - p) / fact(p)

Else

txtComb.Text = ""

MsgBox "Erro: dados inválidos!", vbOKOnly

End If

End Sub

Private Sub cmdSair_Click()

End

End Sub

Function fact(n As Integer) As Double

Dim x As Integer, f As Double

f = 1

For x = 2 To n

f = f * x

Next

fact = f

End Function