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(O)~ 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47 ,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。

Explicit
Private Const mstrFORMATDEFAULT As String = "#.##"
Private mstrParam1 As String, mstrParam2 As String
Private mstrOperate As String
Private Sub cmdAdd_Click()
mstrParam1 = Trim mstrOperate = "+"
___ nil
= & mstrParam1 & vbCrLf
= & mstrOperate & vbCrLf
End Sub
Private Sub cmdPlus_Click()
mstrParam1 = Trim
mstrOperate = "-"
____ Illi
= & mstrParam1 & vbCrLf
= & mstrOperate & vbCrLf
End Sub
Private Sub cmdMultiple_Click()
mstrParam1 = Trim mstrOperate = "*"
____ Illi
= & mstrParam1 & vbCrLf
= & mstrOperate & vbCrLf
End Sub
Private Sub cmdDevide_Click()
mstrParam1 = Trim mstrOperate = "/"
____ Illi
= & mstrParam1 & vbCrLf
= & mstrOperate & vbCrLf
End Sub
Private Sub cmdDot_Click()
Dim mstrShow As String
Dim i As Integer
mstrShow = "."
i = InStr(1, , mstrShow)
If i <= 0 Then
= & mstrShow
End If
End Sub
Private Sub cmdMinuse_Click()
Dim mstrShow As String
Dim i As Integer
mstrShow = "-"
i = InStr(1, , mstrShow)
If i <= 0 Then
= mstrShow &
Else
= Right, Len - 1)
End If
End Sub
Private Sub cmdNumber_Click(Index As Integer)
Dim mstrShow As String
mstrShow = Index
= & mstrShow
End Sub
Private Sub cmdClear_Click()
Illi
End Sub
Private Sub cmdResult_Click()
Dim vParam1 As Variant, vParam2 As Variant Dim vResult As Variant Dim strResult As String
Dim i As Long
Dim blnBeforeDot As Boolean
Dim lngDotPos As Long
Dim blnMinuse As Boolean
mstrParam2 = Trim
= & mstrParam2 & vbCrLf
vParam1 = 0 blnBeforeDot = True lngDotPos = -1 blnMinuse = False
For i = 1 To Len(mstrParam1)
If IsNumeric(Mid(mstrParam1, i, 1)) = True Then
If blnBeforeDot = True Then
vParam1 = vParam1 * 10 + CByte(Mid(mstrParam1, i, 1)) Else
vParam1 = vParam1 + CByte(Mid(mstrParam1, lngDotPos))
End If
ElseIf Mid(mstrParam1, i, 1) = "." Then blnBeforeDot = False lngDotPos = i
ElseIf Mid(mstrParam1, i, 1) = "-" Then blnMinuse = True
End If
Next i
If blnMinuse = True Then vParam1 = -vParam1
End If
vParam2 = 0 blnBeforeDot = True lngDotPos = -1 blnMinuse = False For i = 1 To Len(mstrParam2)
If IsNumeric(Mid(mstrParam2, i, 1)) = True Then
If blnBeforeDot = True Then
vParam2 = vParam2 * 10 + CByte(Mid(mstrParam2, i, 1)) Else
vParam2 = vParam2 + CByte(Mid(mstrParam2, lngDotPos)) End If
ElseIf Mid(mstrParam2, i, 1) = "." Then blnBeforeDot = False lngDotPos = i
ElseIf Mid(mstrParam2, i, 1) = "-" Then blnMinuse = True
End If
Next i
If blnMinuse = True Then vParam2 = -vParam2
End If
Select Case mstrOperate
Case "+"
vResult = vParam1 + vParam2
Case "-"
vResult = vParam1 - vParam2
Case "*"
vResult = vParam1 * vParam2
Case "/" vResult = vParam1 / vParam2
End Select i, 1)) * A (i -
i, 1)) * A (i -
= & "=" & vbCrLf
strResult = Format(vResult, mstrFORMATDEFAULT) = strResult
= & strResult & vbCrLf
End Sub
Private Sub Form_Load()
Illi
Illi
End Sub。