我的表达式编译器，不知错在那里？惨啊

Question

Option Explicit
Public i As Integer, j As Integer, str1 As StringDim optr(0 To 10) As String, opnd(0 To 10) As String
Dim Precede(0 To 4, 0 To 4) As Integer
Private Sub Command1_Click()
Precede(0, 0) = 1
Precede(0, 1) = 1
Precede(0, 2) = -1
Precede(0, 3) = -1
Precede(0, 4) = 1
Precede(1, 0) = 1
Precede(1, 1) = 1
Precede(1, 2) = -1
Precede(1, 3) = -1
Precede(1, 4) = 1
Precede(2, 0) = 1
Precede(2, 1) = 1
Precede(2, 2) = 1
Precede(2, 3) = 1
Precede(2, 4) = 1
Precede(3, 0) = 1
Precede(3, 1) = 1
Precede(3, 2) = 1
Precede(3, 3) = 1
Precede(3, 4) = 1
Precede(4, 0) = -1
Precede(4, 1) = -1
Precede(4, 2) = -1
Precede(4, 3) = -1
Precede(4, 4) = 0
i = 0
j = 0
Text2.Text = Getexp(Text1.Text)
End Sub
Private Function Getexp(str1 As String) As String
Dim C1 As String, x As String, a As String, b As String, theta As String
C1 = ReadChar(str1)
Call pushoptr("#")
Do While getoptr() <> "#"
If "0" <= C1 <= "9" Then
pushopnd (C1)ElseSelect Case pre(getoptr(), C1)
Case -1
pushoptr (C1)Case 0
x = popoptr()
Case 1
theta = popoptr()
b = popopnd()
a = popopnd()
pushopnd (operate(a, theta, b))End SelectEnd If
Loop
Getexp = getopnd()
End Function
Private Function ReadChar(str1 As String) As String
ReadChar = ""
If str1 = "" Then Exit Function
ReadChar = Left(str1, 1)
str1 = Right(str1, Len(str1) - 1)
End Function
Public Function pushoptr(s As String) As String
i = i + 1
optr(i) = s
If (optr(0) = "#") ThenLabel1.Caption = "efdsf"
End If
End Function
Public Function popoptr() As String
i = i - 1
popoptr = optr(i)
End Function
Public Function getoptr() As String
getoptr = optr(i)
End Function
Public Function pushopnd(n As String) As String
j = j + 1
opnd(j) = n
End Function
Public Function popopnd() As String
j = j - 1
popopnd = opnd(j)
End Function
Public Function getopnd() As String
getopnd = opnd(j)
End FunctionPublic Function pre(c2 As String, C1 As String) As Integer
Dim n1 As Integer, n2 As Integer
Select Case c2
Case "+"
n1 = 0
Case "-"
n1 = 1
Case "*"
n1 = 2
Case "/"
n1 = 3
Case "#"
n1 = 4
End SelectSelect Case C1
Case "+"
n2 = 0
Case "-"
n2 = 1
Case "*"
n2 = 2
Case "/"
n2 = 3
Case "#"
n2 = 4
End Select
pre = Precede(n1, n2)
End Function
Public Function operate(a As String, theta As String, b As String) As String
Dim ret As Integer
Select Case theta
Case "+"
ret = Val(a) + Val(b)
Case "-"
ret = Val(a) - Val(b)
Case "*"
ret = Val(a) * Val(b)
Case "/"
ret = Val(a) \ Val(b)
End Select
operate = Str(ret)
End Function

Answer 1

Public Sub InitPriorityTable()
    PriorityTable(1, 1) = 1
    PriorityTable(1, 2) = 1
    PriorityTable(1, 3) = -1
    PriorityTable(1, 4) = -1
    PriorityTable(1, 5) = -1
    PriorityTable(1, 6) = -1
    PriorityTable(1, 7) = 1
    PriorityTable(1, 8) = 1
    
    PriorityTable(2, 1) = 1
    PriorityTable(2, 2) = 1
    PriorityTable(2, 3) = -1
    PriorityTable(2, 4) = -1
    PriorityTable(2, 5) = -1
    PriorityTable(2, 6) = -1
    PriorityTable(2, 7) = 1
    PriorityTable(2, 8) = 1
    
    PriorityTable(3, 1) = 1
    PriorityTable(3, 2) = 1
    PriorityTable(3, 3) = 1
    PriorityTable(3, 4) = 1
    PriorityTable(3, 5) = -1
    PriorityTable(3, 6) = -1
    PriorityTable(3, 7) = 1
    PriorityTable(3, 8) = 1
    
    PriorityTable(4, 1) = 1
    PriorityTable(4, 2) = 1
    PriorityTable(4, 3) = 1
    PriorityTable(4, 4) = 1
    PriorityTable(4, 5) = -1
    PriorityTable(4, 6) = -1
    PriorityTable(4, 7) = 1
    PriorityTable(4, 8) = 1
    
    PriorityTable(5, 1) = 1
    PriorityTable(5, 2) = 1
    PriorityTable(5, 3) = 1
    PriorityTable(5, 4) = 1
    PriorityTable(5, 5) = -1
    PriorityTable(5, 6) = -1
    PriorityTable(5, 7) = 1
    PriorityTable(5, 8) = 1
    
    PriorityTable(6, 1) = -1
    PriorityTable(6, 2) = -1
    PriorityTable(6, 3) = -1
    PriorityTable(6, 4) = -1
    PriorityTable(6, 5) = -1
    PriorityTable(6, 6) = -1
    PriorityTable(6, 7) = 0
    PriorityTable(6, 8) = 10
    
    PriorityTable(7, 1) = 1
    PriorityTable(7, 2) = 1
    PriorityTable(7, 3) = 1
    PriorityTable(7, 4) = 1
    PriorityTable(7, 5) = 1
    PriorityTable(7, 6) = 10
    PriorityTable(7, 7) = 1
    PriorityTable(7, 8) = 1
    
    PriorityTable(8, 1) = -1
    PriorityTable(8, 2) = -1
    PriorityTable(8, 3) = -1
    PriorityTable(8, 4) = -1
    PriorityTable(8, 5) = -1
    PriorityTable(8, 6) = -1
    PriorityTable(8, 7) = 10
    PriorityTable(8, 8) = 20
End Sub
Public Function WordCheck(Func As String, UnknowNum As Double)         '后一个是代表未知数x
Dim i As Integer     'Func 中的第几个字母
Dim j As Integer     'Word中的第几个词
Dim Flag As Boolean    'flag=true 表示上一个字母是 0，2、、、9，和小数点,
Dim k As Integer     'Num 有多少个数
Dim Num(1 To 100) As String    '保存数字
Dim Length As Integer   'Func的长度
Dim Char As String      '取字母
Dim m As Integer
Dim n As Integer
Dim HaveDot As Boolean
Dim ForeWord As Double         '储存整数部分
Dim BehindWord As Double        '储存小数部分
    ForeWord = 0
    BehindWord = 0
    HaveDot = False
    k = 0
    j = 1
    Word(j) = "#"
    Flag = False
    Func = Func & "#"
    Length = Len(Func)
    
    For i = 1 To Length
       Char = Mid(Func, i, 1)
       Select Case Char
           Case 0 To 9, "."
                  k = k + 1
                  Num(k) = Char
                  Flag = True
                  GoTo 10
           Case "+", "-", "*", "/", "^", "(", ")", "#", "x", "X"  '代表结束的"#"
                  If Flag = True Then
                      For m = 1 To k          'm是小数点所在位置
                          If Num(m) = "." Then
                               HaveDot = True
                               Exit For
                          End If
                      Next m
                      If Not HaveDot Then
                          j = j + 1
                          Word(j) = 0
                          For n = 1 To k
                               Word(j) = Word(j) + Num(n) * 10 ^ (k - n)
                          Next n
                      Else
                          For n = 1 To m - 1
                               ForeWord = ForeWord + (Num(n) * 10 ^ (m - n - 1))    '整数部分
                          Next n

Answer 2

                          For n = m + 1 To k
                               On Error GoTo 20:
                               BehindWord = BehindWord + (Num(n) * 10 ^ ((-1) * (n - m)))   '小数部分
                          Next n
                          j = j + 1
                          Word(j) = ForeWord + BehindWord
                          ForeWord = 0
                          BehindWord = 0
                      End If
                      k = 0
                  End If
                  j = j + 1
                  If Char = "X" Or Char = "x" Then
                      Word(j) = UnknowNum
                  Else
                      Word(j) = Char
                  End If
                  Flag = False
        End Select
10:
     Next i
     Exit Function
20:
     HasError = True
End Function
Public Function Operate() As Double
Dim Row As Integer '列
Dim Line As Integer '行
Dim Prianswer As Integer
Dim i As Integer
    InitPriorityTable
    ActionStack.Top = 0
    DataStack.Top = 0
    i = 1
    ActionPushIn (Word(i))
    Do While (True)
        i = i + 1
        On Error GoTo 20:
        Select Case Word(i)
            Case "+", "-", "*", "/", "^", "(", ")", "ln", "#"
                    Select Case ActionStack.Action(ActionStack.Top)
                         Case "+"
                             Line = 1
                         Case "-"
                             Line = 2
                         Case "*"
                             Line = 3
                         Case "/"
                             Line = 4
                         Case "^"
                             Line = 5
                         Case "("
                             Line = 6
                         Case ")"
                             Line = 7
                         Case "#"
                             Line = 8
                   End Select
                   Select Case Word(i)
                         Case "+"
                             Row = 1
                         Case "-"
                             Row = 2
                         Case "*"
                             Row = 3
                         Case "/"
                             Row = 4
                         Case "^"
                             Row = 5
                         Case "("
                             Row = 6
                         Case ")"
                             Row = 7
                         Case "#"
                             Row = 8
                   End Select
                   Prianswer = TableCheck(Line, Row)
                   Select Case Prianswer
                         Case -1   '栈顶优先级低
                             ActionPushIn (Word(i))
                         Case 1     '栈顶高,弹出运算
                             Select Case ActionStack.Action(ActionStack.Top)
                                    Case "+"
                                          DataStack.Data(DataStack.Top - 1) = DataStack.Data(DataStack.Top - 1) + DataStack.Data(DataStack.Top)
                                          ActionOut
                                          DataOut
                                          i = i - 1
                                    Case "-"
                                           DataStack.Data(DataStack.Top - 1) = DataStack.Data(DataStack.Top - 1) - DataStack.Data(DataStack.Top)
                                           ActionOut
                                           DataOut
                                           i = i - 1
                                    Case "*"
                                           DataStack.Data(DataStack.Top - 1) = DataStack.Data(DataStack.Top - 1) * DataStack.Data(DataStack.Top)
                                           ActionOut
                                           DataOut
                                           i = i - 1
                                    Case "/"
                                           DataStack.Data(DataStack.Top - 1) = DataStack.Data(DataStack.Top - 1) / DataStack.Data(DataStack.Top)
                                           ActionOut
                                           DataOut
                                           i = i - 1
                                    Case "^"
                                           DataStack.Data(DataStack.Top - 1) = DataStack.Data(DataStack.Top - 1) ^ DataStack.Data(DataStack.Top)
                                           ActionOut
                                           DataOut
                                           i = i - 1
                                    Case "("   '正确的情况下是不可能出现的情况
                                           HasError = True
                                           Exit Function
                               End Select
                          Case 0
                               ActionOut
                          Case 10
                               HasError = True
                               Exit Function
                          Case 20
                                  '下一个是"#",DataStack中应该只有一个“#”，ActionStack中应该只有一个操作数，否则可看作是错误的结果
                               If DataStack.Top <> 1 Or ActionStack.Top <> 1 Or ActionStack.Action(1) <> "#" Then
                                       HasError = True
                                       Exit Function
                               Else
                                       Operate = DataStack.Data(1)
                                       Exit Function
                               End If
                    End Select
            Case Else                 '操作数
                    DataPushIn (Word(i))
        End Select
    Loop
    Exit Function
20:
    HasError = True
End Function
可以算+，-*，/,^,(,)

Answer 3

这是我以前写的，可以对表达式判断对错，
是积分运算的一部分。当时，我是用这个算一些输入的表达式比较简单的函数，
其中算小数的一部分好象可以用数据类型直接转换，
当时只想到那个苯方法。
还有几个函数：
Public Function DataPushIn(Num As Double)
    DataStack.Top = DataStack.Top + 1
    DataStack.Data(DataStack.Top) = Num
End FunctionPublic Sub DataOut()
    DataStack.Top = DataStack.Top - 1
End SubPublic Function ActionPushIn(Operation As String)
    ActionStack.Top = ActionStack.Top + 1
    ActionStack.Action(ActionStack.Top) = Operation
End FunctionPublic Sub ActionOut()
     ActionStack.Top = ActionStack.Top - 1
End SubPublic Function TableCheck(ActNum1 As Integer, ActNum2 As Integer) As Integer
    TableCheck = PriorityTable(ActNum1, ActNum2)
End Function