MDAS Calculation Using a Class

Submitted by janobe on Sunday, January 5, 2014 - 20:34.

In this tutorial I will teach you how to create the MDAS calculation within the class using Visual Basic 2008. This will help you organize your code and minimize bunch of codes in your Windows Form. MDAS stands for Multiplication, Division, Addition and Subtraction. Let’s begin: Open Visual Basic 2008, create a Project named “MDAS” and set up your Form just like this. MDAS FORM

Add a new file which is a class and name it “calculate”. After that, do this code inside the class.

Public Class calculate
    'declare a private variable as a double
    Private _num1 As Double
    Private _num2 As Double
    Private _total As Double
 
    'set a readonly property for the total of the MDAS
    ReadOnly Property total() As Double
        Get
            Return _total 'return the total
        End Get
    End Property
    'create a property for a private variable so that you can access it
    Property num1() As Double
        Get
            Return _num1  'return the first value
        End Get
        Set(ByVal value As Double)
            _num1 = value 'set the first value
        End Set
    End Property
    Property num2() As Double
        Get
            Return _num2
        End Get
        Set(ByVal value As Double)
            _num2 = value
        End Set
    End Property
 
    'create the sub procedures of the MDAS
    Public Sub multiply()
        'formula of multiplication
        _total = num1 * num2
    End Sub
    Public Sub divide()
        'formula of division
        _total = num1 / num2
    End Sub
    Public Sub add()
        'formula of addition
        _total = num1 + num2
    End Sub
    Public Sub subtract()
        'formula of subtraction
        _total = num1 - num2
    End Sub  
End Class

Go back to the Design Views, double click the Form and create a sub procedure for the clicking event of the radio button.

Public Class Form1
    
    'create a sub procedure for the events of clicking the radio button that handles all of it.
    Private Sub RadioButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) _
     Handles Radio_Subtaction.Click, Radio_Multiplication.Click, Radio_Division.Click, Radio_Addition.Click
 
        'call a constructor method and return to cal as an instance of a class
        Dim cal As calculate = New calculate()
 
        'declaring the string variable represent as a textbox
        Dim txtnum1 As String = TextBox1.Text
        Dim txtnum2 As String = TextBox2.Text
        'declaring the double variable
        Dim dbl_val1 As Double
        Dim dbl_val2 As Double
 
        If IsNumeric(txtnum1) And IsNumeric(txtnum2) Then 'check if the textbox has a numeric value
            'convert the string to double
            dbl_val1 = Double.Parse(txtnum1)
            dbl_val2 = Double.Parse(txtnum2)
 
            'get the value of the converted variable 
            'to pass it into the variable in the class
            cal.num1 = dbl_val1
            cal.num2 = dbl_val2
 
            'the condition is, if the radiobutton is clicked, 
            'the operation of MDAS executes.
            If Radio_Multiplication.Checked Then
                'result:
                cal.multiply() 'call a subname in a class for multiplying
            ElseIf Radio_Division.Checked Then
                'result:
                cal.divide() 'call a subname in a class for dividing
            ElseIf Radio_Addition.Checked Then
                'result:
                cal.add() 'call a subname in a class for adding
            ElseIf Radio_Subtaction.Checked Then
                'result:
                cal.subtract() 'call a subname in a class for subtracting
            End If
        Else
            'the result is: 
            'if the textbox is empty or has a string value
            TextBox3.Text = "Enter a number"
            Return
        End If
        'put the result of the MDAS to a textbox.
        TextBox3.Text = cal.total()
    End Sub
End Class

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