求vb二维数组下标

Private Sub Command1_Click()
Dim a(1 To 3, -100 To 100) As Integer, b(4) As Integer
boundA a, b
Debug.Print "第一维下标为："; b(1), "第一维上标为："; b(2), "第二维下标为："; b(3), "第二一维上标为："; b(4)
End Sub
Public Sub boundA(a() As Integer, b() As Integer)
b(1) = LBound(a, 1)
b(2) = UBound(a, 1)
b(3) = LBound(a, 2)
b(4) = UBound(a, 2)
End Sub

问题貌似：随机产生一个二维数组a(m,n)，求出最大元素值的下标（x,y)

如果这样理解正确的话，代码如下：

（不用任何控件，把代码粘贴上就可以运行）
Private Sub Form_Click()
Dim A() As Integer, M As Integer, N As Integer
Dim I As Integer, J As Integer, X As Integer, Y As Integer
M = Int(Val(InputBox("二维数组的行数", "输入", 5)))
N = Int(Val(InputBox("二维数组的列数", "输入", 7)))
ReDim A(M, N)
Randomize
For I = 1 To M
For J = 1 To N
A(I, J) = Int(Rnd * 100)
Print A(I, J);
Next
Print
Next
X = 1
Y = 1
For I = 1 To M
For J = 1 To N
If A(X, Y) < A(I, J) Then
X = I
Y = J
End If
Next
Next
Print "最大值元素坐标是 A（"; X; "，"; Y; "）="; A(X, Y)
End Sub

是下界吧？
用LBound函数：LBound(array,dim)
其中array是数组名，dim是数组维数
例如：
Public Sub main()
Dim a(1 To 4,6 To 8) As Long
MsgBox LBound(a, 1) '显示1
MsgBox LBound(a, 2) '显示6
MsgBox UBound(a, 1) '显示4
MsgBox UBound(a, 2) '显示8
End Sub

Dim maxi As Integer

Public Sub maxnum(n As Integer)
For i = 0 To UBound(n)
If n(i) > maxn Then maxn = n(i): maxi = i
Next i
End Sub

maxi就是