vb求素数程序

1、需要在窗体放置4个控件，不用设置控件任何属性：Command1，Command2，List1，Label1Dim ctExit As Boolean, ctStop As BooleanDim ctCiFind As Long, ctCiAdd As LongPrivate Sub Form_Load() Me.Caption = 查找 N 以内的所有素数 Label1.Caption = Me.Caption: Label1.AutoSize = True Command1.Caption = 查找: Command2.Caption = 取消End SubPrivate Sub Form_

2、Resize() Dim S As Long On Error Resume Next S = Me.TextWidth(A) Command1.Move S, S, S * 8, S * 3 Command2.Move S * 10, S, S * 8, S * 3 Label1.Move S, Me.ScaleHeight - S * 4, Label1.Width, S * 4 List1.Move 0, S * 5, Me.ScaleWidth, Label1.Top - S * 5End SubPrivate Sub Form_Unload(Cancel As Integer) ct

3、Exit = True: ctStop = True 保证在查找未结束时能顺利结束程序End SubPrivate Sub Command2_Click() ctStop = True 取消查找End SubPrivate Sub Command1_Click() Static N As Long Dim Su() As Long, S As Long, Gen As Long, I As Long, J As Long Dim nStr As String, T As Single, Ci As Long 查找 N 以内的所有素数，存入数组 Su()，素数的总个数为 S If N 1 the

4、n S = 1: Su(1)=2 根据冰麟轻武的建议，添加了本行 ctStop = False: Command1.Enabled = False List1.Clear: Label1.Caption = 正在查找 & N & 以内的素数 . DoEvents T = Timer If ctCiFind ctCiFind Then Ci = 0: DoEvents If ctStop Then GoTo Show1 Label1.Caption = N & 以内的素数： & S & 个， & Format(I / N * 100, 0.0) & % End If 用 I 除以已经找到的素数交

5、换下面两行代码，似乎能减少一次 Mod 运算 If I Mod Su(J) = 0 Then GoTo NextI 能整除，不是素数，检查下一个 If Su(J) Gen Then Exit For 检测到大于 I 的平方根就不用查了。删除此语句，结果一样，但速度慢得多 Next S = S + 1: ReDim Preserve Su(S): Su(S) = INextI: Next I = N 将找到的素数显示到列表框中Show1: If ctExit Then Exit Sub T = Timer - T Ci = I / T * 0.3 调整为查找过程中每 0.3 秒刷新一次进度 If

6、 ctCiFind 65535 Then I = 65534 Else I = S List1.Visible = False If ctCiAdd ctCiAdd Then Ci = 0: DoEvents If ctStop Then Exit For Label1.Caption = 添加到到列表框 & Format(J / S * 100, 0.0) & % End If Next T = Timer - T Ci = J / T * 0.3 调整为添加过程中每 0.3 秒刷新一次进度 If ctCiAdd Ci Then ctCiAdd = Ci If List1.ListCount

7、 0 Then Load Label1(I): Label1(I).Visible = True Label1(I).Move Me.ScaleWidth * Rnd, Me.ScaleHeight * Rnd Label1(I).Tag = Rnd * 7 - 3 & | & Rnd * 5 + 1 Label1(I).Font.Size = 5 + Rnd * 9 Next Label1(0).Font.Size = 9 Timer1.Enabled = True: Timer1.Interval = 50End SubPrivate Sub Timer1_Timer() Dim I As

8、 Long, S As Long, T As Single, L As Single Dim nTag As String, X As Single, y As Single, W As Single Randomize W = Label1(0).Height * 0.05 For I = 0 To Label1.Count - 1 nTag = Label1(I).Tag S = InStr(nTag, |) X = Left(nTag, S - 1): y = Mid(nTag, S + 1) S = Int(Rnd * 10) If S = 0 Then X = Rnd * 11 - 5: Label1(I).Tag = X & | & y L = Label1(I).Left + X * W: T = Label1(I).Top + y * W If L -Label1(I).Width Then L = Me.ScaleWidth If T Me.ScaleWidth Then L = -Label1(I).Wid