The Code

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Public Class Form83

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    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

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        '## Example 20.1 : Shopping Cart ##
        '## In this example, we add a few Labels, two Buttons, ## 
        '## and six Check Boxes. We declare the price of each item using the Const                          Keyword. ##

        '## If a Checkbox is being ticked, its state is True else its state is False. ##
        '## To calculate the total amount of purchase, ##
        '## we use the mathematical operator +=. For example, sum+=BN is actually                      sum=sum+BN. ##

        '## Finally, we use the ToString method to display the amount in currency. ##

 

        '## Dimension Variables using (Const) Declaration ##

        '## Indicate Value is a Constant & Cannot be Changed ##

        Const LX As Integer = 100
        Const BN As Integer = 500
        Const SD As Integer = 200
        Const HD As Integer = 80
        Const HM As Integer = 300
        Const AM As Integer = 150
        Dim c As String = "n2"

        Dim sum As Integer

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        '##Conditional Operator using If... Then... Else Operator. ##

        '## (sum += value) implies as (Sum = Sum + Value) ## 

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        If CheckBox1.Checked = True Then
            sum += LX
        End If

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        If CheckBox2.Checked = True Then
            sum += BN
        End If

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        If CheckBox3.Checked = True Then
            sum += SD
        End If

        If CheckBox4.Checked = True Then
            sum += HD
        End If

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        If CheckBox5.Checked = True Then
            sum += HM
        End If

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        If CheckBox6.Checked = True Then
            sum += AM

        End If

        Label1.Text = sum.ToString("c")

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    End Sub

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    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

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        '## Button 2 - Clear CheckBox ##

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        CheckBox1.Checked = False
        CheckBox2.Checked = False
        CheckBox3.Checked = False
        CheckBox4.Checked = False
        CheckBox5.Checked = False
        CheckBox6.Checked = False

        Label1.Text = ""

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    End Sub

End Class

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