Public Class calcArea
    'Operands
    Private num1 As Double
    Private num2 As Double
    'Temporary values
    Private tempValue As Double
    'Memory storage
    Private Memory As Double
    'True if "," is use else false
    Private hasDecimal As Boolean
    Private inputStatus As Boolean
    Private clearText As Boolean
    'Operator
    Private calcFunction As String

#Region "Number Buttons"
    Private Sub Btn_0_Click(sender As Object, e As EventArgs) Handles btn_0.Click
        If inputStatus = False Then
            If lbl_input.Text.Length >= 1 Then
                lbl_input.Text += btn_0.Text

            End If
        End If
    End Sub

    Private Sub Btn_1_Click(sender As Object, e As EventArgs) Handles btn_1.Click
        If inputStatus = False Then
            lbl_input.Text += btn_1.Text
        Else
            lbl_input.Text = btn_1.Text
            inputStatus = False
        End If
    End Sub

    Private Sub Btn_2_Click(sender As Object, e As EventArgs) Handles btn_2.Click
        If inputStatus = False Then
            lbl_input.Text += btn_2.Text
        Else
            lbl_input.Text = btn_2.Text
            inputStatus = False
        End If
    End Sub

    Private Sub Btn_3_Click(sender As Object, e As EventArgs) Handles btn_3.Click
        If inputStatus = False Then
            lbl_input.Text += btn_3.Text
        Else
            lbl_input.Text = btn_3.Text
            inputStatus = False
        End If
    End Sub

    Private Sub Btn_4_Click(sender As Object, e As EventArgs) Handles btn_4.Click
        If inputStatus = False Then
            lbl_input.Text += btn_4.Text
        Else
            lbl_input.Text = btn_4.Text
            inputStatus = False
        End If
    End Sub

    Private Sub Btn_5_Click(sender As Object, e As EventArgs) Handles btn_5.Click
        If inputStatus = False Then
            lbl_input.Text += btn_5.Text
        Else
            lbl_input.Text = btn_5.Text
            inputStatus = False
        End If
    End Sub

    Private Sub Btn_6_Click(sender As Object, e As EventArgs) Handles btn_6.Click
        If inputStatus = False Then
            lbl_input.Text += btn_6.Text
        Else
            lbl_input.Text = btn_6.Text
            inputStatus = False
        End If
    End Sub

    Private Sub Btn_7_Click(sender As Object, e As EventArgs) Handles btn_7.Click
        If inputStatus = False Then
            lbl_input.Text += btn_7.Text
        Else
            lbl_input.Text = btn_7.Text
            inputStatus = False
        End If
    End Sub

    Private Sub Btn_8_Click(sender As Object, e As EventArgs) Handles btn_8.Click
        If inputStatus = False Then
            lbl_input.Text += btn_8.Text
        Else
            lbl_input.Text = btn_8.Text
            inputStatus = False
        End If
    End Sub

    Private Sub Btn_9_Click(sender As Object, e As EventArgs) Handles btn_9.Click
        If inputStatus = False Then
            lbl_input.Text += btn_9.Text
        Else
            lbl_input.Text = btn_9.Text
            inputStatus = False
        End If
    End Sub

#End Region

#Region "Calculation Buttons"
    Private Sub Btn_plus_Click(sender As Object, e As EventArgs) Handles btn_plus.Click
        If lbl_input.Text.Length <> 0 Then
            If calcFunction = String.Empty Then
                num1 = CDbl(lbl_input.Text)
                lbl_input.Text = String.Empty
            Else
                CalculateTotals()
            End If
            calcFunction = "Add"
            hasDecimal = False

        End If
    End Sub

    Private Sub Btn_minus_Click(sender As Object, e As EventArgs) Handles btn_minus.Click
        If lbl_input.Text.Length <> 0 Then
            If calcFunction = String.Empty Then
                num1 = CDbl(lbl_input.Text)
                lbl_input.Text = String.Empty
            Else
                CalculateTotals()
            End If
            calcFunction = "Substract"
            hasDecimal = False
        End If
    End Sub

    Private Sub Btn_slash_Click(sender As Object, e As EventArgs) Handles btn_slash.Click
        If lbl_input.Text.Length <> 0 Then
            If calcFunction = String.Empty Then
                num1 = CDbl(lbl_input.Text)
                lbl_input.Text = String.Empty
            Else
                CalculateTotals()
            End If
            calcFunction = "Divide"
            hasDecimal = False
        End If
    End Sub

    Private Sub Btn_mpp_Click(sender As Object, e As EventArgs) Handles btn_mpp.Click
        If lbl_input.Text.Length <> 0 Then
            If calcFunction = String.Empty Then
                num1 = CDbl(lbl_input.Text)
                lbl_input.Text = String.Empty
            Else
                CalculateTotals()
            End If
            calcFunction = "Multiply"
            hasDecimal = False
        End If
    End Sub

    Private Sub Btn_upper_Click(sender As Object, e As EventArgs) Handles btn_upper.Click
        If lbl_input.Text.Length <> 0 Then
            If calcFunction = String.Empty Then
                num1 = CDbl(lbl_input.Text)
                lbl_input.Text = String.Empty
            Else
                CalculateTotals()
            End If
            calcFunction = "PowerOf"
            hasDecimal = False
        End If
    End Sub

    Private Sub Btn_sqrt_Click(sender As Object, e As EventArgs) Handles btn_sqrt.Click
        If lbl_input.Text.Length <> 0 Then
            tempValue = CDbl(lbl_input.Text)
            tempValue = System.Math.Sqrt(tempValue)
                lbl_input.Text = CStr(tempValue)
                hasDecimal = False
            End If
    End Sub

    Private Sub Btn_equal_Click(sender As Object, e As EventArgs) Handles btn_equal.Click
        If lbl_input.Text.Length <> 0 AndAlso num1 <> 0 Then
            CalculateTotals()
            calcFunction = ""
        hasDecimal = False
        End If
    End Sub

    Private Sub Btn_below_Click(sender As Object, e As EventArgs) Handles btn_below.Click
        If lbl_input.Text.Length <> 0 Then
            tempValue = CDbl(lbl_input.Text)
            tempValue = 1 / tempValue
            lbl_input.Text = CStr(tempValue)
            hasDecimal = False
        End If
    End Sub

    Private Sub Btn_plusminus_Click(sender As Object, e As EventArgs) Handles btn_plusminus.Click
        If inputStatus = False Then
            If lbl_input.Text.Length > 0 Then
                tempValue = -1 * CDbl(lbl_input.Text)
                lbl_input.Text = CStr(tempValue)
            End If
        End If
    End Sub


#End Region

#Region "Other Buttons"
    Private Sub Btn_CE_Click(sender As Object, e As EventArgs) Handles btn_CE.Click
        lbl_input.Text = String.Empty
        hasDecimal = False
    End Sub

    Private Sub Btn_C_Click(sender As Object, e As EventArgs) Handles btn_C.Click
        lbl_input.Text = String.Empty
        num1 = 0
        num2 = 0
        calcFunction = String.Empty
        hasDecimal = False
    End Sub

    Private Sub Btn_backspace_Click(sender As Object, e As EventArgs) Handles btn_backspace.Click
        Dim str As String
        Dim loc As Integer
        If lbl_input.Text.Length > 0 Then
            str = lbl_input.Text.Chars(lbl_input.Text.Length - 1)
            If str = "." Then
                hasDecimal = False
            End If
            loc = lbl_input.Text.Length
            lbl_input.Text = lbl_input.Text.Remove(loc - 1, 1)
        End If
    End Sub

    Private Sub Btn_dot_Click(sender As Object, e As EventArgs) Handles btn_dot.Click
        If Not inputStatus Then
            If Not hasDecimal Then
                If lbl_input.Text.Length >= 1 Then
                    If Not lbl_input.Text = "0" Then
                        lbl_input.Text += ","
                        hasDecimal = True
                    End If
                Else
                    lbl_input.Text = "0"
                End If
            End If
        End If
    End Sub
#End Region

#Region "Helpers"
    Private Sub CalculateTotals()
        num2 = CDbl(lbl_input.Text)
        Select Case calcFunction
            Case "Add"
                num1 = num1 + num2
            Case "Substract"
                num1 = num1 - num2
            Case "Divide"
                num1 = num1 / num2
            Case "Multiply"
                num1 = num1 * num2
            Case "PowerOf"
                num1 = System.Math.Pow(num1, num2)
        End Select
        lbl_input.Text = CStr(num1)
        inputStatus = True
    End Sub


#End Region
End Class