Chapter 4, Problem 2E

Explanation of Solution

Program

Public Class frmMain

'Declaring variables of type double and initializing with values

'variable twin

Dim twin As Double = 39.99

'variable full

Dim full As Double = 49.99

'variable queen

Dim queen As Double = 49.99

'variable king

Dim king As Double = 69.99

'variable totalCost

Dim totalCost As Double = 0

'variable shippingFee

Dim shippingFee As Double

'calculating total cost after clicking on button

Private Sub btnCost_Click(sender As Object, e As EventArgs) Handles btnCost.Click

'displaying total cost in textbox and Math.Round() is used to round the totalcost to two decimal places

txtCost.Text = String.Format("$" + Math.Round((totalCost + shippingFee), 2).ToString())

End Sub

'exit button click

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

Application.Exit()

End Sub

'checkbox CheckedChanged() event

Private Sub chkpickup_CheckedChanged(sender As Object, e As EventArgs) Handles chkpickup.CheckedChanged

'if checkbox is checked then

If (chkpickup.Checked = True) Then

'assign the shipping fee to the variable shippingFee

shippingFee = 5

Else

'else shippingFee is zero

shippingFee = 0

End If

End Sub

'radio button twin CheckedChanged() event

Private Sub rbtTwin_CheckedChanged(sender As Object, e As EventArgs) Handles rbtTwin.CheckedChanged

'if radio button is changed the clear values from textbox

txtCost.Text = ""

If (rbtTwin...