混和计算
已知BUG。1、表达式第一个字符是 运算符时，程序报错。
2、多个加号连在一起，程序会忽略掉。
提供给大家参考，希望能有人优化一下。
程序代码：Option Explicit
Private Sub Command1_Click()
Label1.Caption = "=" & 计算(Text1.Text)
End Sub
Public Function 计算(cs As String) As String
Dim i As Long, j As Long
Dim k As String
Dim k1 As String, k2 As String
Dim k3 As String, k4 As String
Dim bj As Boolean
Dim yy As Long
k4 = cs
'处理括号
If InStr(1, cs, "(") > 0 And InStr(1, cs, ")") > 0 Then '含括号继续
i = InStrRev(k4, "(") '从右向左
Do While i > 0 '找到左括号
j = InStr(i, k4, ")") '寻找最近的右括号
If j = 0 And i > 0 Then '没找到
k4 = "Err" '错误
Exit Do
End If
k4 = Left(k4, i - 1) & 计算(Mid(k4, i + 1, j - i - 1)) & Mid(k4, j + 1) '找到后,计算括号内容
i = InStrRev(k4, "(") '继续查找
'Debug.Print k4 '显示每一步处理后表达式的变化
Loop
End If
If InStr(1, k4, "Err") Then '如果通过计算后,出现了Err ,则立即报Err 给上一层
计算 = "Err"
Exit Function
End If
If InStr(1, k4, "(") > 0 Or InStr(1, k4, ")") > 0 Then '如果通过上面处理后,还含有括号,说明括号不配对
计算 = "Err"
Exit Function
End If
For i = 1 To Len(k4) '从第一个字符向向搜索
k1 = Mid(k4, i, 1)
Select Case k1
Case "*" '乘
If k3 <> "" Then
'先计算,再把结果给K2
k2 = 计算1(k2, k3, yy)
End If
k3 = "" '第二个数为空
bj = True '需要算第二个数
yy = 3 '运算符是 3
Case "/"
If k3 <> "" Then
'先计算,再把结果给K2
k2 = 计算1(k2, k3, yy)
End If
k3 = "" '第二个数为空
bj = True '需要算第二个数
yy = 4 '运算符是 3
Case "+", "-" '要运行,然后把结果给K
'先计算,再把结果给K2
If Mid(k4, i - 1, 1) <> "E" Then '如果不是科学记数法的符号,
If yy = 3 Or yy = 4 Then
k2 = 计算1(k2, k3, yy)
k3 = ""
yy = 0
bj = False
End If
k = k & k2 & k1
k2 = ""
Else '否则保存
If bj Then
k3 = k3 & k1
Else
k2 = k2 & k1
End If
End If
Case "1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "E", "." '允许的合法数据
If bj Then
k3 = k3 & k1
Else
k2 = k2 & k1
End If
End Select
Next i
If yy = 3 Or yy = 4 Then
k2 = 计算1(k2, k3, yy)
End If
k = k & k2
k4 = k
If InStr(1, k4, "Err") Then '如果通过计算后,出现了Err ,则立即报Err 给上一层
计算 = "Err"
Exit Function
End If
k2 = "": k3 = "": k1 = "" '临时变量全为空
yy = 0
bj = False '设置为没有运算过,如果少了一句,会吃掉第一个数据
For i = 1 To Len(k4) '从第一个字符向向搜索
k1 = Mid(k4, i, 1)
Select Case k1
Case "+" '加
If Mid(k4, i - 1, 1) <> "E" Then
If k3 <> "" Then
'先计算,再把结果给K2
k2 = 计算1(k2, k3, yy)
End If
k3 = "" '第二个数为空
bj = True '需要算第二个数
yy = 1 '运算符是 3
Else
If bj Then
k3 = k3 & k1
Else
k2 = k2 & k1
End If
End If
Case "-" '减
If Mid(k4, i - 1, 1) <> "E" Then
If k3 <> "" Then
'先计算,再把结果给K2
k2 = 计算1(k2, k3, yy)
End If
k3 = "" '第二个数为空
bj = True '需要算第二个数
yy = 2 '运算符是 2
Else
If bj Then
k3 = k3 & k1
Else
k2 = k2 & k1
End If
End If
Case "1", "2", "3", "4", "5", "6", "7", "8", "9", "0", ".", "E"
If bj Then
k3 = k3 & k1
Else
k2 = k2 & k1
End If
End Select
Next i
k2 = 计算1(k2, k3, yy)
计算 = k2
End Function
Public Function 计算1(cs1 As String, cs2 As String, cs3 As Long) As String
If IsNumeric(cs1) And IsNumeric(cs2) Then
If InStr(1, cs1, "Err") > 0 Or InStr(1, cs2, "Err") > 0 Then
计算1 = "Err"
Exit Function
End If
Select Case cs3
Case 0 '运算符为0,直接返回第一个参数
计算1 = cs1
Case 1 '加
计算1 = Val(cs1) + Val(cs2)
Case 2 '减
计算1 = Val(cs1) - Val(cs2)
Case 3 '乘
计算1 = Val(cs1) * Val(cs2)
Case 4 '除
计算1 = Val(cs1) / Val(cs2)
End Select
Else
计算1 = "Err"
End If
End Function
