Option Explicit

Dim potflag As Integer '标识是否用小数点

Dim numcol As Integer ' 点击运算符的个数

Dim LastInput ' 指示上一次操作的内容

Dim colflag 'numcol为1时，保存运算符

Dim temp1,temp2 '分别保存运算符两端的运算数

Private Sub CmdCel_Click() '重新开始计算按钮，个计量数和标识初始化

Res = Format(0,"0.")

temp1 = 0

temp2 = 0

numcol = 0

potflag = False

LastInput = "cel" '标识此操作为"cel"

End Sub

Private Sub CmdPot_Click() '使用小数点

If LastInput <> "num" Then

Res = Format(0,"0.")

ElseIf String(1,Res) = "-" Then

Res = Format(0,"-0.")

End If

potflag = True

LastInput = "num" '标识此操作为"num"

End Sub

Private Sub Cmdsign_Click() '使用正负号

If String(1,Res) <> "-" Then '如果当前是正数添加负号

Res = "-" & Res

Else: Res = Right(Res,Len(Res) - 1) '如果当前是证号，取消负号

End If

LastInput = "num" '标识此操作为"num"

End Sub

Private Sub ComCol_Click(Index As Integer) '点击操作符，可进行连续运算

numcol = numcol + 1 '通过numcol标识点击运算符的次数

If numcol = 1 Then '当前数为操作符左侧运算数时，记录当前操作数

temp1 = Res

Res = Format(0,"0.")

ElseIf numcol = 2 Then '当前操作数为操作符右侧数，进行相应运算

temp2 = Res

Select Case colflag

Case "+"

temp1 = CDbl(temp1) + CDbl(temp2)

Case "-"

temp1 = CDbl(temp1) - CDbl(temp2)

Case "*"

temp1 = CDbl(temp1) * CDbl(temp2)

Case "/"

If temp2 = 0 Then

MsgBox "输入错误，除数不能为0",vbOKOnly,"提示"

Else: temp1 = CDbl(temp1) / CDbl(temp2)

End If

Case "="

Res = temp2

End Select

Res = temp1

numcol = 0

End If

colflag = ComCol(Index).Caption '记录该次选择的操作符

LastInput = "col" '标识此操作为"col"

End Sub

Private Sub ComNum_Click(Index As Integer) '点击数字按钮

If LastInput <> "num" Then '显示需要先判断是否启用小数点，再选择显示的方法

Res = Format(0,".")

potflag = False

End If If potflag Then

Res = Res + ComNum(Index).Caption

Else: Res = Left(Res,InStr(Res,Format(0,".")) - 1) + ComNum(Index).Caption + Format(0,".")

End If

LastInput = "num" '标识此操作为"num"

End Sub

Private Sub Res_Change() 'Res为操作数和计算结果显示的文本框

End Sub