【算法】VB实现后缀表达式转中缀表达式

后缀表达式转中缀表达式代码如下：

Public Function TrueBackToMid(ByVal strBack As String) As String
    Dim i As Long
    Dim opCode() As String
'    Stop
    Dim ops1 As String, ops2 As String, opC As String '计算符表示，【保留】
    '初始化堆栈
        WorkStack.Clear '保留
    '堆栈初始化结束
    opCode = Split(strBack, ",")
'    Stop
    For i = 0 To UBound(opCode)
        If IsSymbolEx(opCode(i)) Then
'        Stop
            op2 = WorkStack.Pop
            op1 = WorkStack.Pop
            WorkStack.Push "(" & op1 & opCode(i) & op2 & ")"
        Else
'        Stop
            WorkStack.Push opCode(i)
        End If
    Next i
    op1 = WorkStack.Pop
    If Len(op1) > 2 Then
        op1 = Mid(op1, 2, Len(op1) - 2)
    End If
    
    TrueBackToMid = op1
End Function

其中使用了堆栈类:http://www.cnblogs.com/sunsoftresearch/archive/2013/04/23/3037271.html

还使用了判断字符是否为符号的函数：

Public Function IsSymbolEx(ByVal strs As String) As Boolean
    IsSymbolEx = True
    Select Case strs
        Case "+"
        Case "-"
        Case "*"
        Case "/"
        Case Else
            IsSymbolEx = False
    End Select
End Function

有问题欢迎留言