Dim N As Integer
Dim Jc As Single
N = Int(Val(InputBox("0——50之間的整數", "輸入", 26)))
If N > 50 Or N < 0 Then
MsgBox "錯誤!請輸入0——50之間的整數"
Exit Sub
End If
Jc = JmIg(N)
Print N; "! ="; Jc
End Sub
Function JmIg(X As Integer) As Single
If X = 0 Then JmIg = 1 Else JmIg = X * JmIg(X - 1)
End Function