(加试题)王老师在使用 VB 程序要实现 n! 的功能。
Private Sub Command1_Click()
Dim p As Integer
Dim sum As Long
p = Val(Text1.Text)
sum = fx(p)
Text2.Text = CStr(sum)
End Sub
Function fx(x As Integer) As Long
If x = 1 Then
fx = 1
Else
fx =____________________
End If
End Function
要该程序实现此功能,横线处的代码为( )
A.x(x)*(x-1) | B.fx(x)*x | C.fx(x-1)*x | D.fx(x-1)*(x-1) |