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 hum = 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345,输出结果是______。