[填空题] 编写如下通用过程： Sub proc(By Val num As Long，ByRef ren As Long)Dim k As LongK = 1num=Abs(num)Do Whil

[填空题] 编写如下通用过程：

Sub proc(By Val num As Long，ByRef ren As Long)

Dim k As Long

K = 1

num=Abs(num)

Do While num

k= k *(num Mod 10)

num=num 10

Loop

ren=k

End Sub

在窗体上画一个命令按钮，然后编写如下事件过程：

Private Sub Command1 Click()

Dim n As Long， r As Long

n=InputBox("请输入一个整数")

n = CLng(n)

proc n，r

Print r

End Sub

程序运行后，单击命令按钮，在输入对话框中输入345，输出结果是 【15】 。