程序代码：

Dim i As String
Dim J As Long

i = InputBox("请输入")

If IsNumeric(i) Then
    J = CLng(i)
Else
    J = 0
End If

If J < 10 Then
    J = 1
ElseIf J < 100 Then
    J = 2
ElseIf J < 1000 Then
    J = 3
Else
    J = 4
End If

On J GoTo Re1, Re2, Re3

    MsgBox "默认分支"
    GoTo Rend:

Re1:
    MsgBox "第一个分支"
    GoTo Rend:

Re2:
    MsgBox "第二个分支"
    GoTo Rend:

Re3:
    MsgBox "第三个分支"
    GoTo Rend:

Rend:

    MsgBox "结束"