图1
   图2

 程序代码如下：

Private Sub Command1_Click()

  Dim i As Integer

  List1.Clear            '清除列表框内容

End Sub

Private Function f(x As Integer) As Boolean  '自定义函数f,返回值为逻辑型

  Dim j As Integer

  f = True

  For j = 2 To Int(Sqr(x))

    If x Mod j = 0 Then

      f =     ③      '函数返回值

      Exit For           '跳出For循环

    End If

  Next j

End Function

Dim a(1 To 1000) As Integer

Dim n As Integer

Private Sub Form_Load()

‘确定n的值和数组a的各个元素值，即每根棍子的长度值，代码略

End Sub

Function max(x As Integer, y As Integer) As Integer

If x > y Then

    max=x

  Else

    max=y

  End If

End Function

Private Sub Command1_Click()

  Dim i As Integer , j As Integer , k As Integer

  Dim ans As Integer , c As Integer , longest As Integer , rest As Integer

ans=0

  ‘让 i<j<k,保证棍子不会重复选中

  For i=1 To n

  For j=i+1 To n

   For k=j+1 To n

    c=a(i)+a(j)+a(k)

    longest=     ‘①

    rest=c-longest    ‘rest 保存最短的两条边的和

    If  Then    ‘②

     ans=max(ans , c)

End If

   Next k

Next j

  Next i

Print ans

End Sub

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