' 写得不太规范,只是大致意思。Option ExplicitPrivate Sub Command1_Click() Debug.Print Factorial(20, 20 - 7 + 1) / Factorial(7, 1) End SubPrivate Function Factorial(ByVal a As Long, ByVal b As Long) As Double Dim r As Double, i As Double r = 1 For i = b To a r = r * i Next i Factorial = r End Function
Debug.Print Factorial(20, 20 - 7 + 1) / Factorial(7, 1)
End SubPrivate Function Factorial(ByVal a As Long, ByVal b As Long) As Double
Dim r As Double, i As Double
r = 1
For i = b To a
r = r * i
Next i
Factorial = r
End Function