Question

图中的vb题目如何做

Answer 1

Dim n As Integer, sum As Integer

Private Sub Command1_Click()

  Dim a(20) As Integer

  List1.Clear

  Label1.Caption = ""

  k = 0

  If n = 0 Then List2.Clear

  For i = 1 To 20

    a(i) = Rnd * 501 + 100

    List1.AddItem a(i)

    yes = True

    For j = 2 To Sqr(a(i))

      If a(i) Mod j = 0 Then

        yes = False

        Exit For

      End If

    Next j

    If yes Then k = k + 1

  Next i

  n = n + 1

  sum = sum + k

  List2.AddItem "第" & n & "组：" & k & "个素数"

End Sub

Private Sub Command2_Click()

  Label1.Caption = n & "组，共" & sum & "个"

  n = 0

  sum = 0

End Sub

Private Sub Form_Load()

  Label1.Caption = ""

End Sub

追问

朋友，为什么程序中if语句中，没有end if 做结束语句。

还有sum 没有赋初始值，可以直接sum =sum +k吗

初学者，请多多指教。谢谢！