Template for Calculator in Visual Basic (some bugs may occur)

Public Class frmCalculator

    Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click

        'Retrieve two numbers from textboxes and add them together

        'then display operator and result

        Dim strNumber As String

        Dim dblNum1 As Double

        Dim dblNum2 As Double

        Dim dblTotal As Double

        'if both are numeric complete the operation and display total

        If IsNumeric(tbNumTwo.Text) And IsNumeric(tbNumOne.Text) Then

            dblNum1 = Convert.ToDouble(tbNumOne.Text)

            dblNum2 = Convert.ToDouble(tbNumTwo.Text)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = False

            dblTotal = dblNum1 + dblNum2

            lblMath.Text = "(+) Plus"

            lblEquals.Text = "= " & dblTotal.ToString("G")

            'if only first textbox has a numeric value

            'store it in a string variable and request entry for second textbox

        ElseIf IsNumeric(tbNumOne.Text) Then

            strNumber = tbNumOne.Text

            dblNum1 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = True

            tbNumTwo.Focus()

            lblEquals.Text = "?"

            'if only second textbox has a numeric value

            'store it in a string variable and request entry for first textbox

        ElseIf IsNumeric(tbNumTwo.Text) Then

            strNumber = tbNumTwo.Text

            dblNum2 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = False

            tbNumOne.Focus()

            lblEquals.Text = "?"

            'else request a number for both

        Else

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = True

            tbNumOne.Focus()

            lblEquals.Text = "?"

        End If

    End Sub

    Private Sub btnSubtract_Click(sender As Object, e As EventArgs) Handles btnSubtract.Click

        'Retrieve two numbers from textboxes and subtract second number from first number

        'then display operator and result

        Dim strNumber As String

        Dim dblNum1 As Double

        Dim dblNum2 As Double

        Dim dblTotal As Double

        'if both are numeric complete the operation and display total

        If IsNumeric(tbNumTwo.Text) And IsNumeric(tbNumOne.Text) Then

            dblNum1 = Convert.ToDouble(tbNumOne.Text)

            dblNum2 = Convert.ToDouble(tbNumTwo.Text)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = False

            dblTotal = dblNum1 - dblNum2

            lblMath.Text = "(-) Minus"

            lblEquals.Text = "= " & dblTotal.ToString("G")

            'if only first textbox has a numeric value

            'store it in a string variable and request entry for second textbox

        ElseIf IsNumeric(tbNumOne.Text) Then

            strNumber = tbNumOne.Text

            dblNum1 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = True

            tbNumTwo.Focus()

            lblEquals.Text = "?"

            'if only second textbox has a numeric value

            'store it in a string variable and request entry for first textbox

        ElseIf IsNumeric(tbNumTwo.Text) Then

            strNumber = tbNumTwo.Text

            dblNum2 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = False

            tbNumOne.Focus()

            lblEquals.Text = "?"

            'else request a number for both

        Else

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = True

            tbNumOne.Focus()

            lblEquals.Text = "?"

        End If

    End Sub

    Private Sub btnMultiply_Click(sender As Object, e As EventArgs) Handles btnMultiply.Click

        'Retrieve two numbers from textboxes and multiply them together

        'then display operator and result

        Dim strNumber As String

        Dim dblNum1 As Double

        Dim dblNum2 As Double

        Dim dblTotal As Double

        'if both are numeric complete the operation and display total

        If IsNumeric(tbNumTwo.Text) And IsNumeric(tbNumOne.Text) Then

            dblNum1 = Convert.ToDouble(tbNumOne.Text)

            dblNum2 = Convert.ToDouble(tbNumTwo.Text)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = False

            dblTotal = dblNum1 * dblNum2

            lblMath.Text = "(*) Times"

            lblEquals.Text = "= " & dblTotal.ToString("G")

            'if only first textbox has a numeric value

            'store it in a string variable and request entry for second textbox

        ElseIf IsNumeric(tbNumOne.Text) Then

            strNumber = tbNumOne.Text

            dblNum1 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = True

            tbNumTwo.Focus()

            lblEquals.Text = "?"

            'if only second textbox has a numeric value

            'store it in a string variable and request entry for first textbox

        ElseIf IsNumeric(tbNumTwo.Text) Then

            strNumber = tbNumTwo.Text

            dblNum2 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = False

            tbNumOne.Focus()

            lblEquals.Text = "?"

            'else request a number for both

        Else

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = True

            tbNumOne.Focus()

            lblEquals.Text = "?"

        End If

       

    End Sub

    Private Sub btnExponent_Click(sender As Object, e As EventArgs) Handles btnExponent.Click

        'Retrieve two numbers from textboxes and use the order of the first number to the power of the second number

        'then display operator and result

        Dim strNumber As String

        Dim dblNum1 As Double

        Dim dblNum2 As Double

        Dim dblTotal As Double

        'if both are numeric complete the operation and display total

        If IsNumeric(tbNumTwo.Text) And IsNumeric(tbNumOne.Text) Then

            dblNum1 = Convert.ToDouble(tbNumOne.Text)

            dblNum2 = Convert.ToDouble(tbNumTwo.Text)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = False

            dblTotal = dblNum1 ^ dblNum2

            lblMath.Text = "(^) To The Power Of"

            lblEquals.Text = "= " & dblTotal.ToString("G")

            'if only first textbox has a numeric value

            'store it in a string variable and request entry for second textbox

        ElseIf IsNumeric(tbNumOne.Text) Then

            strNumber = tbNumOne.Text

            dblNum1 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = True

            tbNumTwo.Focus()

            lblEquals.Text = "?"

            'if only second textbox has a numeric value

            'store it in a string variable and request entry for first textbox

        ElseIf IsNumeric(tbNumTwo.Text) Then

            strNumber = tbNumTwo.Text

            dblNum2 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = False

            tbNumOne.Focus()

            lblEquals.Text = "?"

            'else request a number for both

        Else

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = True

            tbNumOne.Focus()

            lblEquals.Text = "?"

        End If

      

    End Sub

    Private Sub btnDivide_Click(sender As Object, e As EventArgs) Handles btnDivide.Click

        'Retrieve two numbers from textboxes and divide the first number by the second number

        'then display operator and result

        Dim strNumber As String

        Dim dblNum1 As Double

        Dim dblNum2 As Double

        Dim dblTotal As Double

        'if both are numeric complete the operation and display total

        If IsNumeric(tbNumTwo.Text) And IsNumeric(tbNumOne.Text) Then

            dblNum1 = Convert.ToDouble(tbNumOne.Text)

            dblNum2 = Convert.ToDouble(tbNumTwo.Text)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = False

            dblTotal = dblNum1 / dblNum2

            lblMath.Text = "(/) Divided By"

            lblEquals.Text = "= " & dblTotal.ToString("G")

            'if only first textbox has a numeric value

            'store it in a string variable and request entry for second textbox

        ElseIf IsNumeric(tbNumOne.Text) Then

            strNumber = tbNumOne.Text

            dblNum1 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = True

            tbNumTwo.Focus()

            lblEquals.Text = "?"

            'if only second textbox has a numeric value

            'store it in a string variable and request entry for first textbox

        ElseIf IsNumeric(tbNumTwo.Text) Then

            strNumber = tbNumTwo.Text

            dblNum2 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = False

            tbNumOne.Focus()

            lblEquals.Text = "?"

            'else request a number for both

        Else

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = True

            tbNumOne.Focus()

            lblEquals.Text = "?"

        End If

       

    End Sub

    Private Sub btnIntDivide_Click(sender As Object, e As EventArgs) Handles btnIntDivide.Click

        'Retrieve two numbers from textboxes and divide the first number by the second number

        'then display operator and result as a whole number

        Dim strNumber As String

        Dim dblNum1 As Double

        Dim dblNum2 As Double

        Dim intTotal As Integer

        'if both are numeric complete the operation and display total

        If IsNumeric(tbNumTwo.Text) And IsNumeric(tbNumOne.Text) Then

            dblNum1 = Convert.ToDouble(tbNumOne.Text)

            dblNum2 = Convert.ToDouble(tbNumTwo.Text)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = False

            intTotal = dblNum1 \ dblNum2

            lblMath.Text = "(\) Interger Divided By"

            lblEquals.Text = "= " & intTotal.ToString("G")

            'if only first textbox has a numeric value

            'store it in a string variable and request entry for second textbox

        ElseIf IsNumeric(tbNumOne.Text) Then

            strNumber = tbNumOne.Text

            dblNum1 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = True

            tbNumTwo.Focus()

            lblEquals.Text = "?"

            'if only second textbox has a numeric value

            'store it in a string variable and request entry for first textbox

        ElseIf IsNumeric(tbNumTwo.Text) Then

            strNumber = tbNumTwo.Text

            dblNum2 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = False

            tbNumOne.Focus()

            lblEquals.Text = "?"

            'else request a number for both

        Else

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = True

            tbNumOne.Focus()

            lblEquals.Text = "?"

        End If

       

    End Sub

    Private Sub btnModulus_Click(sender As Object, e As EventArgs) Handles btnModulus.Click

        'Retrieve two numbers from textboxes and divide the first number by the second number

        'then display operator and result as only the remainer from dividing

        Dim strNumber As String

        Dim dblNum1 As Double

        Dim dblNum2 As Double

        Dim intTotal As Integer

        'if both are numeric complete the operation and display total

        If IsNumeric(tbNumTwo.Text) And IsNumeric(tbNumOne.Text) Then

            dblNum1 = Convert.ToDouble(tbNumOne.Text)

            dblNum2 = Convert.ToDouble(tbNumTwo.Text)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = False

            intTotal = dblNum1 Mod dblNum2

            lblMath.Text = "MOD"

            lblEquals.Text = "= " & intTotal.ToString("G")

            'if only first textbox has a numeric value

            'store it in a string variable and request entry for second textbox

        ElseIf IsNumeric(tbNumOne.Text) Then

            strNumber = tbNumOne.Text

            dblNum1 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = False

            lblRequestTwo.Visible = True

            tbNumTwo.Focus()

            lblEquals.Text = "?"

            'if only second textbox has a numeric value

            'store it in a string variable and request entry for first textbox

        ElseIf IsNumeric(tbNumTwo.Text) Then

            strNumber = tbNumTwo.Text

            dblNum2 = Convert.ToDouble(strNumber)

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = False

            tbNumOne.Focus()

            lblEquals.Text = "?"

            'else request a number for both

        Else

            lblRequestOne.Visible = True

            lblRequestTwo.Visible = True

            tbNumOne.Focus()

            lblEquals.Text = "?"

        End If

       

    End Sub

    Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click

        'Clear will empty the textboxes and operator label

        'then place the focus on the first text boxes

        tbNumOne.Text = ""

        tbNumTwo.Text = ""

        lblMath.Text = ""

        lblEquals.Text = ""

        lblRequestOne.Visible = False

        lblRequestTwo.Visible = False

        tbNumOne.Focus()

    End Sub

    Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click

        'Exit will call the close function

        Close()

    End Sub

End Class