下标越界（求助）

[gogold]

Option Explicit
Dim a(3) As Single '边长
Dim b(4) As Single

Private Sub Command1_Click(Index As Integer)
Dim s As Single
Dim a() As Single
Select Case Index
Case 0 '计算
a(3) = (Sqr((2 * a(0) * a(1)) / a(2)))
b(4) = ((6 * a(0)) / 2)
Text1(3).Text = Trim(a(3))
Text1(4).Text = Trim(b(4))

Case 1 '清除
For s = 0 To 6
Text1(s).Text = "": a(s) = 0
Next
Case 2 '退出
End
End Select
End Sub

Private Sub Text1_Change(Index As Integer)
If Val(Text1(Index).Text) <= 0 Then Text1(Index) = "": Exit Sub '禁止输入非正数
a(Index) = Val(Text1(Index).Text) '赋值三边
End Sub

[wanbotang]

问题在此处吧：
For s = 0 To 6
Text1(s).Text = "": a(s) = 0
Next
你的定义：Dim a(3) As Single
a()定义只有3个元素，而你有7个文本框，肯定会出现下标越界。
改成这样应该行:
For s = 0 To 6
Text1(s).Text = ""
If s<2 then a(s) = 0
Next

[superauu]

什么地方出错了啊

[wanbotang]

而你在时间过程中又定义：Dim a() As Single为动态数组，这里和上面那个a(3)有冲突。
要么你就用ReDim语句。

[gogold]

改了你这种，但还是出现了下标越界呀

[gogold]

呵呵，谢谢呀，我太不细心了，终于按照你的做法做到了。十分感谢ProgramFanA(零零发)

[wanbotang]

那里出现下标越界啊，你那段代码做什么用的，没看明白。

[gogold]

其实这是一个求解三角形面积的代码，我把他改成了按照批量订购模型的公式来做，只不过是改公式呀

[diclover]

这属于覆盖的问题,当你定义了一个和全局变量同名的局部变量时,局部变量将覆盖全局变量.
所以你的a(3) = (Sqr((2 * a(0) * a(1)) / a(2)))中的a(0),a(1),a(2),a(3)都会越界改成这样:
Option Explicit
Dim a(3) As Single '边长
Dim b(4) As Single

Private Sub Command1_Click(Index As Integer)
Dim s As Single
Dim a() As Single

Select Case Index
Case 0 '计算
Redim a(3) as single
a(3) = (Sqr((2 * a(0) * a(1)) / a(2)))
b(4) = ((6 * a(0)) / 2)
Text1(3).Text = Trim(a(3))
Text1(4).Text = Trim(b(4))

Case 1 '清除
For s = 0 To 6
Redim a(s) as Single
Text1(s).Text = "": a(s) = 0
Next
Case 2 '退出
End
End Select
End Sub

Private Sub Text1_Change(Index As Integer)
If Val(Text1(Index).Text) <= 0 Then Text1(Index) = "": Exit Sub '禁止输入非正数
a(Index) = Val(Text1(Index).Text) '赋值三边
End Sub