图 a
。
图 b
图 c
图 d
Private Sub Command1_Click()
Dim n As Integer, i As Integer, s As String
Dim mid As Integer
n = Val(Text1.Text)
If ① Then
Text2.Text = "输入错误,请输入偶数!"
Else
mid = n \ 2 + 1
s = ""
For i = 2 To n
If i = n Then
s = s + "2"
Else
s = s + ② + ","
End If
Next i
③
End If
End Sub
① ② ③