Dim a(1 To 10)As Integer

    Function find(L As Integer，R As Integer，key As Integer)As Integer

    If L>R Then

        find=0：Exit Functionhp

    ElseIf a(L)>=key Then

        find=L：Exit Function

  Else

           ①  

        If a(M)<key Thenhp

              find=find(M+1，R，key)

         ElseIf    ②     Then

              find=find(L，M-1，key)

         Else

              find=M

         End If

     End If

End Function

Private Sub Command1 Click()

    Dim k As Integer

    Dim P As Integer

    k=Val(Text1．Text)

         ③  

    Text2．Text=a(P)

    Text3．Text=Str(P)

    If p=0 Then

       Text2．Text=“无”

    End If

End Sub

Private Sub Form Load()

    a(1)=3：a(2)=3：a(3)=3：a(4)=4：a(5)=7：a(6)=7

    a(7)=10：a(8)=13：a(9)=19：a(10)=21

    For i=1 To 10

        List1．AddItem Str(a(i))

    Next i

End Sub

① ② ③