程序代码：

Dim a As Integer, b As String, fnext As Integer
Dim d As Double
Private Sub c_Click()
If fnext = 1 Then
  Select Case b
         Case "+"
              d = Val(Text1) + a
         Case "-"
              d = a - Val(Text1)
         Case "*"
              d = a * Val(Text1)
         Case "/"
              If Val(Text1) = 0 Then
                MsgBox "0"
               Else
                d = a / Val(Text1)
              End If
  End Select
End If
If fnext = 1 Then
    Text1 = d
    fnext = 0
End If
End Sub

Private Sub c1_Click(Index As Integer)
  Text1 = Text1 & c1(Index).Caption
End Sub


Private Sub cmdcount_Click(Index As Integer)
If fnext = 0 Then
    a = Val(Text1)
    b = cmdcount(Index).Caption
    fnext = 1
    Text1 = ""
End If
End Sub