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)
答案:C