在窗体上画一个名称为Command1的命令按钮,然后编写如下事件过程:
Private Function fun1(n As Integer) As Integer
Dim k As Integer
If n=1 Then
k=1
Else
k=1+fun1(n-1)*2
End If
fun1=k
End Function
Private Sub Command1_Click()
Dim m As Integer,x As Integer
x=4
m=fun1(x)
Print m
End Sub
程序运行后,单击命令按钮,则窗体上显示的内容是______。
A) 4
B) 6
C) 9
D) 15