Option Explicit
Dim lastinput As String
Dim NumOp As Integer
Dim PreOp As String
Dim DeFlag
Dim Op1
Dim Op2

Private Sub cmd_Percent_Click()
Dim var As Single
var = Val(lblOut.Caption)
lblOut.Caption = Str(var)
End Sub

Private Sub cmd0_Click()
      number (0)
End Sub

Private Sub cmd1_Click()
      number (1)
End Sub

Private Sub cmd2_Click()
      number (2)
End Sub

Private Sub cmd3_Click()
      number (3)
End Sub

Private Sub cmd4_Click()
      number (4)
End Sub

Private Sub cmd5_Click()
      number (5)
End Sub

Private Sub cmd6_Click()
      number (6)
End Sub

Private Sub cmd7_Click()
      number (7)
End Sub

Private Sub cmd8_Click()
      number (8)
End Sub

Private Sub cmd9_Click()
      number (9)
End Sub

Private Sub cmdC_Click()
  Form_Load
End Sub

Private Sub cmdCE_Click()
      lblOut.Caption = "0."
      DeFlag = False
      lastinput = "icon"
End Sub

Private Sub cmdDecimal_Click()
If lastinput = "negative" Then
   lblOut.Caption = "-0."
ElseIf lastinput <> "number" Then
   lblOut.Caption = "0."
End If
DeFlag = True
lastinput = "number"
End Sub

Private Sub cmdDiv_Click()
If lastinput = "number" Then
   NumOp = NumOp + 1
End If
If NumOp = 1 Then
    Op1 = lblOut.Caption
ElseIf NumOp = 2 Then
    Op2 = lblOut.Caption
    calculation
End If
If lastinput <> "negative" Then
   lastinput = "icon"
   PreOp = "/"
End If
End Sub

Private Sub cmdEqual_Click()
If lastinput = "number" Then
   NumOp = NumOp + 1
End If
If NumOp = 1 Then
   Op1 = lblOut.Caption
ElseIf NumOp = 2 Then
   Op2 = lblOut.Caption
   calculation
End If
If lastinput <> "negative" Then
   lastinput = "icon"
   PreOp = "="
End If
End Sub

Private Sub cmdMinus_Click()
If lastinput = "number" Then
   NumOp = NumOp + 1
End If
If NumOp = 0 Then
  If lastinput <> "negative" Then
  lblOut.Caption = "-" + lblOut.Caption
  lastinput = "negative"
End If
ElseIf NumOp + 2 Then
   Op2 = lblOut.Caption
   calculation
End If

If lastinput <> "negative" Then
   lastinput = "icon"
   PreOp = "-"
End If
End Sub

Private Sub cmdMul_Click()
If lastinput = "number" Then
   NumOp = NumOp + 1
End If
If NumOp = 1 Then
     Op1 = lblOut.Caption
ElseIf NumOp = 2 Then
     Op2 = lblOut.Caption
     calculation
End If

If lastinput <> "negative" Then
   lastinput = "icon"
   PreOp = "x"
End If
End Sub

Private Sub cmdPlus_Click()
If lastinput = "number" Then
   NumOp = NumOp + 1
End If
If NumOp = 1 Then
   Op1 = lblOut.Caption
ElseIf NumOp = 2 Then
   Op2 = lblOut.Caption
   calculation
End If

If lastinput <> "negative" Then
   lastinput = "icon"
   PreOp = "-"
End If
End Sub

Private Sub Form_Load()
lblOut.Caption = "0"
DeFlag = False
NumOp = 0
lastinput = "No"
PreOp = " "
Op1 = 0
Op2 = 0
End Sub

Private Sub number(num As Integer)
Dim temp As String
If lastinput <> "number" Then
lblOut.Caption = "."
  DeFlag = False
End If
If DeFlag Then
  lblOut.Caption = lblOut.Caption + Str(num)
Else
 temp = lblOut.Caption
 temp = Left(temp, Len(temp) - 1)
 lblOut.Caption = temp + Str(num) + "."
 End If
 If lastinput = "negative" Then
    lblOut.Caption = "-" + lblOut.Caption
End If
lastinput = "number"
End Sub

Private Sub calculation()
Select Case PreOp
  Case "+"
    Op1 = Val(Op1) + Val(Op2)
  Case "-"
    Op1 = Val(Op1) - Val(Op2)
  Case "x"
    Op1 = Val(Op1) * Val(Op2)
  Case "/"
    If Val(Op2) = 0 Then
         MsgBox "Sorry,zero can't be divided", vbCritical, "Calculator"
    Else
      Op1 = Val(Op1) / Val(Op2)
    End If
  Case "="
    Op1 = Op2
End Select
lblOut.Caption = Op1
NumOp = 1
End Sub