VB6.0的小程序计算器对于刚入门学习VB6的朋友来说肯定会做些小程序吧，这里就是给大家演示个简单的计算器程序，仅供参考啦。
界面上加减乘除四个按钮分别是cmdAdd、cmdPlus、cmdMultiple、cmdDevide，小数点按钮是cmdDot，负号按钮是cmdMinuse，数字0～9为了偷懒，用了控件数组cmdNumber(0)~ cmdNumber(9)，上面txtShow是显示数字和结果用的，txtOperate是显示中间步骤的。
思路大致是这样，点加减乘除这类操作符的时候，把当前txtShow的值保存在模块变量mstrParam1里，同时把操作符保存到mstrOperate里，按等于号时把先把当前txtShow的值保存在模块变量mstrParam2里，然后对mstrParam1和mstrParam2进行运算，当然要记得设法把String转换成数值进行运算。
转换的过程要注意，这里是用的Variant数据类型，vParam1和vParam2都是Variant 类型，保存的是mstrParam1和mstrParam2的数值。
之所以不用integer、long、double 这些标准类型，是因为这些类型都有大小限制，做出来用着不方便，VB最大的整型long才到 2147483647，这意味着计算器的计算结果只能限制在9位到10位。
而Variant类型可以支持非常大的数，具体多大不清楚，但起码几十位是能够支持的。
另外，最后算完的结果也要做格式化，因为如果数值非常大的话，VB会自动转成科学计数法，所以要用Format函数进行调整。
如果需要源代码的话在我百度空间里留言。
/zhaozhigang517Option ExplicitPrivate Const mstrFORMATDEFAULT As String = "#.##"Private mstrParam1 As String, mstrParam2 As StringPrivate mstrOperate As StringPrivate Sub cmdAdd_Click()mstrParam1 = Trim(txtShow.Text)mstrOperate = "+"txtShow.Text = ""txtOperate.Text = txtOperate.Text & mstrParam1 & vbCrLf txtOperate.Text = txtOperate.Text & mstrOperate & vbCrLfEnd SubPrivate Sub cmdPlus_Click()mstrParam1 = Trim(txtShow.Text)mstrOperate = "-"txtShow.Text = ""txtOperate.Text = txtOperate.Text & mstrParam1 & vbCrLf txtOperate.Text = txtOperate.Text & mstrOperate & vbCrLfEnd SubPrivate Sub cmdMultiple_Click()mstrParam1 = Trim(txtShow.Text)mstrOperate = "*"txtShow.Text = ""txtOperate.Text = txtOperate.Text & mstrParam1 & vbCrLf txtOperate.Text = txtOperate.Text & mstrOperate & vbCrLfEnd SubPrivate Sub cmdDevide_Click()mstrParam1 = Trim(txtShow.Text)mstrOperate = "/"txtShow.Text = ""txtOperate.Text = txtOperate.Text & mstrParam1 & vbCrLftxtOperate.Text = txtOperate.Text & mstrOperate & vbCrLfEnd SubPrivate Sub cmdDot_Click()Dim mstrShow As StringDim i As IntegermstrShow = "."i = InStr(1, txtShow.Text, mstrShow)If i <= 0 ThentxtShow.Text = txtShow.Text & mstrShowEnd IfEnd SubPrivate Sub cmdMinuse_Click()Dim mstrShow As StringDim i As IntegermstrShow = "-"i = InStr(1, txtShow.Text, mstrShow)If i <= 0 ThentxtShow.Text = mstrShow & txtShow.TextElsetxtShow.Text = Right(txtShow.Text, Len(txtShow.Text) - 1) End IfEnd SubPrivate Sub cmdNumber_Click(Index As Integer)Dim mstrShow As StringmstrShow = IndextxtShow.Text = txtShow.Text & mstrShowEnd SubPrivate Sub cmdClear_Click()txtShow.Text = ""End SubPrivate Sub cmdResult_Click()Dim vParam1 As Variant, vParam2 As VariantDim vResult As VariantDim strResult As StringDim i As LongDim blnBeforeDot As BooleanDim lngDotPos As LongDim blnMinuse As BooleanmstrParam2 = Trim(txtShow.Text)txtOperate.Text = txtOperate.Text & mstrParam2 & vbCrLfvParam1 = 0blnBeforeDot = TruelngDotPos = -1blnMinuse = FalseFor i = 1 To Len(mstrParam1)If IsNumeric(Mid(mstrParam1, i, 1)) = True ThenIf blnBeforeDot = True ThenvParam1 = vParam1 * 10 + CByte(Mid(mstrParam1, i, 1))ElsevParam1 = vParam1 + CByte(Mid(mstrParam1, i, 1)) * (0.1 ^ (i - lngDotPos))End IfElseIf Mid(mstrParam1, i, 1) = "." ThenblnBeforeDot = FalselngDotPos = iElseIf Mid(mstrParam1, i, 1) = "-" ThenblnMinuse = TrueEnd IfNext iIf blnMinuse = True ThenvParam1 = -vParam1End IfvParam2 = 0blnBeforeDot = TruelngDotPos = -1blnMinuse = FalseFor i = 1 To Len(mstrParam2)If IsNumeric(Mid(mstrParam2, i, 1)) = True ThenIf blnBeforeDot = True ThenvParam2 = vParam2 * 10 + CByte(Mid(mstrParam2, i, 1))ElsevParam2 = vParam2 + CByte(Mid(mstrParam2, i, 1)) * (0.1 ^ (i - lngDotPos))End IfElseIf Mid(mstrParam2, i, 1) = "." ThenblnBeforeDot = FalselngDotPos = iElseIf Mid(mstrParam2, i, 1) = "-" ThenblnMinuse = TrueEnd IfNext iIf blnMinuse = True ThenvParam2 = -vParam2End IfSelect Case mstrOperateCase "+"vResult = vParam1 + vParam2Case "-"vResult = vParam1 - vParam2Case "*"vResult = vParam1 * vParam2Case "/"vResult = vParam1 / vParam2End SelecttxtOperate.Text = txtOperate.Text & "=" & vbCrLfstrResult = Format(vResult, mstrFORMATDEFAULT)txtShow.Text = strResulttxtOperate.Text = txtOperate.Text & strResult & vbCrLfEnd SubPrivate Sub Form_Load()txtShow.Text = ""txtOperate.Text = ""End Sub（注：可编辑下载，若有不当之处，请指正，谢谢!）。