单项选择题

单击一次命令按钮之后，在对话框中输入12，2，34，23，窗体中的输出结果为______ 。 Private Sub Command1_ Click () Dim a(4) As Integer For i = 1 To 4 a (i) = Val (InputBox (“请输入元素”)) Next i plus a(1), a(2), a(3) End Sub Sub plus(first As Integer, second As Integer, third As Integer, Optional forth) n = first + second + third If Not IsMissing (forth) Then n = n + forth End If Print n End Sub