关于实时异常'6'：溢出

关于实时错误'6'：溢出
在窗体上设置了3个文本框和3个命令按钮，通过单击command1,在弹出的对话框中输入学生分数并计算，通过单击command2,在3个文本框中分别显示及格人数，不及格人数和平均分。但是单击command2后，在Text3.Text = Str(total / n)
处总是显示“实时错误6：溢出”。麻烦大家帮我看看是哪里的问题呢？
事件过程如下：

VB code

Dim n As Single   Dim n1 As Single   Dim n2 As Single   Dim total As Single   Dim score As SinglePrivate Sub Command1_Click()start:   score = InputBox("输入分数：")   n = 0: n1 = 0: n2 = 0: total = 0   If score >= 60 And score <= 100 Then      n1 = n1 + 1      total = total + score      n = n + 1   ElseIf score < 60 And score > 0 Then      n2 = n2 + 1      total = total + score      n = n + 1   Else      GoTo finish   End If   GoTo startfinish:End SubPrivate Sub Command2_Click()   Text1.Text = Str(n1)   Text2.Text = Str(n2)   Text3.Text = Str(total / n)End SubPrivate Sub Command3_Click()   n = 0: n1 = 0: n2 = 0: total = 0   EndEnd Sub

VB code

Dim n As LongDim n1 As LongDim n2 As LongPrivate Sub Command2_Click()  Text1.Text = n1  Text2.Text = n2  Text3.Text = total/nEnd Sub
[解决办法]
VB code
Private Sub Command1_Click()start:  ...  n = 0: n1 = 0: n2 = 0: total = 0 '<- 每次循环（包括最后结束时）都清零了  ...  GoTo finish  ...  GoTo startfinish:End SubPrivate Sub Command2_Click()   Text3.Text = Str(total / n) '<- 这里运算 0/0 当然出错了End Sub