Help with Starting out with visual basic 7th edition chapter 6 Programming Chall

Question

Help with Starting out with visual basic 7th edition chapter 6 Programming Challenge 4 Automotive charges .

This is my code:

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        'Class-level declarations

        Const decOIL_Change As Decimal = 36D

        'The oil change charge

        Const decLUBE_JOB As Decimal = 28D

        'The lube job charge

        Const decRADIATOR_FLUSH As Decimal = 50D

        'The radiator flush charge

        Const decTRANSMISSION_FLUSH As Decimal = 120D

        'The transmission flush charge

        Const decINSPECTION As Decimal = 15D

        'The Inspection charge

        Const decMUFFLER_REPLACEMENT As Decimal = 20D

        'The tire rotation charge

        Const decLABOR_PER_MIN As Decimal = 1D

        'The labor charge per minute

        Const decSALES_TAX As Decimal = 0.06D

        'The sales tax for parts

        Private decPARTSCHARGE As Decimal

        'Parts charge

        Private intMinutesOfLabor As Integer

        'Hours of labor

        Private decTotalTaxCharges As Decimal

        'Tax on parts total

        Private decTotalServicesAndLabor As Decimal

        'The total of all services and labor.

        Private decTotalCharges As Decimal

        'Total of all charges

    'Verify that the two input values are valid numbers and

    'neither is less than zero.

    Function ValidateInputs() As Boolean

        If Not Decimal.TryParse(txtParts.Text, decPartsCharge) Or decPartsCharge < 0D Then

            MessageBox.Show("The cost of parts must be a positive real number.", "Invalid Input")

            Return False

        ElseIf Not Integer.TryParse(txtLabor.Text, intMinutesOfLabor) Or intMinutesOfLabor < 0 Then

            MessageBox.Show("Labor minutes must be a positive integer." "Invalid Input")

            Return False

        Else

            Return True

        End If

    End Function

    Sub CalculateTotalCharges()

        Dim decTotalOilAndLubeCharges As Decimal

        'Oil and lube total

        Dim decTotalFlushCharges As Decimal

        'Flushes total

        Dim decTotalMiscCharges As Decimal

        'Miscellaneous total

        Dim decLaborCharges As Decimal

        If Not ValidateInputs() Then

            Exit Sub

        End If

        'Calculate each of the charges.

        decTotalOilAndLubeCharges = CalcOilLubeCharges()

        decTotalFlushCharges = CalcFlushCharges()

        decTotalMiscCharges = CalcMiscCharges()

        decLaborCharges = intMunutesOfLabor * decLABOR_PER_MIN

        decTotalTaxCharges = decPartsCharge * decSALES_TAX

        'Calculate the total of all the services and labor.

        decTotalServicesAndLabor = decTotalOilAndLubeCharges + decTotalFlushCharges +

            decTotalMiscCharges + decLaborCharges

        'Calculate the total charges

        decTotalCharges = decTotalOilAndLubeCharges + decTotalFlushCharges +

            decTotalMiscCharges + decLaborCharges + decPartsCharge + decTotalTaxCharges

        'Calculate all Oil and Lube charges

        Function CalcOilLubeCharges() As Decimal

        'Initialize the total oil and lube charges to zero.

        Dim decTotalOilAndLubeCharges As Decimal = 0D

        'Determine of oil change was checked

        If chkOilChange.Checked Then

            'Apply the oil change charge

            decTotalOilAndLubeCharges += decOIL_CHANGE

        End If

        'Return the oil and lube charges

        Return decTotalOilAndLubeCharges

    End Function

    'Calculate radiator and transmission flush charges

    Function CalcFlushCharges() As Decimal

        'Initialize the total flush charges to zero

        Dim decTotalFlushCharges As Decimal = 0D

        'Determine if radiator flush was checked.

        If chkRadiatorFlush.Checked Then

            'Apply the radiator flush charge

            decTotalFlushCharges += decRADIATOR_FLUSH

        End If

        'Determine if transmission flush was checked

        If chkTransmissionFlush.Checked Then

            'Apply the transmission flush charge

            decTotalFlushCharges += decTRANSMISSION_FLUSH

        End If

        'Return the total flush charges

      Return decTotalFlushCharges

    End Function

    'Calculate inspection, muffler, and tire rotation charges

    Function CalcMiscCharges() As Decimal

        'Initialize the total miscelaneous charges to zero

        Dim decTotalMiscCharges As Decimal = 0D

        'Determine if inspection was checked

        If chkInspection.Checked Then

            'Apply the inspection charge

            decTotalMiscCharges += decINSPECTION

        End If

        'Determine if the muffler replacement was checked

        If chkReplaceMuffler.Checked Then

            'Apply the muffler replacement charge

            decTotalMiscCharges += decMUFFLER_REPLACEMENT

        End If

        'Determine if tire rotation was checked

        If chkTireRotation.Checked Then

            'Apply the tire rotation charge

            decTotalMiscCharges += decTIRE_ROTATION

        End If

        'Return the total miscellaneous charges

        Return decTotalMiscCharges

    End Function

    'Clear the oil change and lube job check boxes

    Sub ClearOilLube()

        chkOilChange.Checked = False

        chkLubeJob.Checked = False

    End Sub

    'Clear the radiator and transmission flush check boxes

    Sub ClearFlushes()

        chkRadiatorFlush.Checked = False

        chkTransmissionFlush.Checked = False

    End Sub

    'Clear the inspection, muffler replacement and the tire rotation check boxes

    Sub ClearMisc()

        chkInspection.Checked = False

        chkReplaceMuffler.Checked = False

        chkTireRotation.Checked = False

    End Sub

    'Clear the parts and labor check boxes

    Sub ClearOther()

        txtParts.Clear()

        txtParts.Clear()

    End Sub

    'Set the text in the summary labels to an empty string

    Sub ClearFees()

        lblServicesAndLabor.Text = String.Empty

        lblParts.Text = String.Empty

        lblTaxOnParts.Text = String.Empty

        lblTotalFees.Text = String.Empty

    End Sub

    Private Sub btnCalculateTotal_Click(sender As Object, e As EventArgs) Handles btnCalculateTotal.Click

        'Display the summary

        lblServicesAndLabor.Text = decTotalServicesAndLabor.ToString("c")

        lblParts.Text = decPartsCharge.ToString("c")

        lblTaxOnParts.Text = decTotalTaxCharges.ToString("c")

        lblTotalFees.Text = decTotalCharges.ToString("c")

    End Sub

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

        'To clear the controls to default values

        ClearOilLube()

        ClearFlushes()

        ClearMisc()

        ClearOther()

        ClearFees()

    End Sub

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

        'Close the form

        Me.Close()

    End Sub

End Class

Can someone please tell me what is wrong with my code and or declarations, Thank you!

Explanation / Answer

A)

Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'Class-level declarations
Const decOIL_Change As Decimal = 36D
'The oil change charge
Const decLUBE_JOB As Decimal = 28D
'The lube job charge
Const decRADIATOR_FLUSH As Decimal = 50D
'The radiator flush charge
Const decTRANSMISSION_FLUSH As Decimal = 120D
'The transmission flush charge
Const decINSPECTION As Decimal = 15D
'The Inspection charge
Const decMUFFLER_REPLACEMENT As Decimal = 20D
'The tire rotation charge
Const decLABOR_PER_MIN As Decimal = 1D
'The labor charge per minute
Const decSALES_TAX As Decimal = 0.06D
'The sales tax for parts
Private decPARTSCHARGE As Decimal
'Parts charge
Private intMinutesOfLabor As Integer
'Hours of labor
Private decTotalTaxCharges As Decimal
'Tax on parts total
Private decTotalServicesAndLabor As Decimal
'The total of all services and labor.
Private decTotalCharges As Decimal
'Total of all charges
'Verify that the two input values are valid numbers and
'neither is less than zero.
Function ValidateInputs() As Boolean
If Not Decimal.TryParse(txtParts.Text, decPartsCharge) Or decPartsCharge < 0D Then
MessageBox.Show("The cost of parts must be a positive real number.", "Invalid Input")
Return False
ElseIf Not Integer.TryParse(txtLabor.Text, intMinutesOfLabor) Or intMinutesOfLabor < 0 Then
MessageBox.Show("Labor minutes must be a positive integer." "Invalid Input")
Return False
Else
Return True
End If
End Function
Sub CalculateTotalCharges()
Dim decTotalOilAndLubeCharges As Decimal
'Oil and lube total
Dim decTotalFlushCharges As Decimal
'Flushes total
Dim decTotalMiscCharges As Decimal
'Miscellaneous total
Dim decLaborCharges As Decimal
If Not ValidateInputs() Then
Exit Sub
End If
'Calculate each of the charges.
decTotalOilAndLubeCharges = CalcOilLubeCharges()
decTotalFlushCharges = CalcFlushCharges()
decTotalMiscCharges = CalcMiscCharges()
decLaborCharges = intMunutesOfLabor * decLABOR_PER_MIN
decTotalTaxCharges = decPartsCharge * decSALES_TAX
'Calculate the total of all the services and labor.
decTotalServicesAndLabor = decTotalOilAndLubeCharges + decTotalFlushCharges +
decTotalMiscCharges + decLaborCharges
'Calculate the total charges
decTotalCharges = decTotalOilAndLubeCharges + decTotalFlushCharges +
decTotalMiscCharges + decLaborCharges + decPartsCharge + decTotalTaxCharges
'Calculate all Oil and Lube charges
Function CalcOilLubeCharges() As Decimal
'Initialize the total oil and lube charges to zero.
Dim decTotalOilAndLubeCharges As Decimal = 0D
'Determine of oil change was checked
If chkOilChange.Checked Then
'Apply the oil change charge
decTotalOilAndLubeCharges += decoil_change
End If
'Return the oil and lube charges
Return decTotalOilAndLubeCharges
End Function
'Calculate radiator and transmission flush charges
Function CalcFlushCharges() As Decimal
'Initialize the total flush charges to zero
Dim decTotalFlushCharges As Decimal = 0D
'Determine if radiator flush was checked.
If chkRadiatorFlush.Checked Then
'Apply the radiator flush charge
decTotalFlushCharges += decRADIATOR_FLUSH
End If
'Determine if transmission flush was checked
If chkTransmissionFlush.Checked Then
'Apply the transmission flush charge
decTotalFlushCharges += decTRANSMISSION_FLUSH
End If
'Return the total flush charges
Return decTotalFlushCharges
End Function
'Calculate inspection, muffler, and tire rotation charges
Function CalcMiscCharges() As Decimal
'Initialize the total miscelaneous charges to zero
Dim decTotalMiscCharges As Decimal = 0D
'Determine if inspection was checked
If chkInspection.Checked Then
'Apply the inspection charge
decTotalMiscCharges += decINSPECTION
End If
'Determine if the muffler replacement was checked
If chkReplaceMuffler.Checked Then
'Apply the muffler replacement charge
decTotalMiscCharges += decMUFFLER_REPLACEMENT
End If
'Determine if tire rotation was checked
If chkTireRotation.Checked Then
'Apply the tire rotation charge
decTotalMiscCharges += decTIRE_ROTATION
End If
'Return the total miscellaneous charges
Return decTotalMiscCharges
End Function
'Clear the oil change and lube job check boxes
Sub ClearOilLube()
chkOilChange.Checked = False
chkLubeJob.Checked = False
End Sub
'Clear the radiator and transmission flush check boxes
Sub ClearFlushes()
chkRadiatorFlush.Checked = False
chkTransmissionFlush.Checked = False
End Sub
'Clear the inspection, muffler replacement and the tire rotation check boxes
Sub ClearMisc()
chkInspection.Checked = False
chkReplaceMuffler.Checked = False
chkTireRotation.Checked = False
End Sub
'Clear the parts and labor check boxes
Sub ClearOther()
txtParts.Clear()
txtParts.Clear()
End Sub
'Set the text in the summary labels to an empty string
Sub ClearFees()
lblServicesAndLabor.Text = String.Empty
lblParts.Text = String.Empty
lblTaxOnParts.Text = String.Empty
lblTotalFees.Text = String.Empty
End Sub
Private Sub btnCalculateTotal_Click(sender As Object, e As EventArgs) Handles btnCalculateTotal.Click
'Display the summary
lblServicesAndLabor.Text = decTotalServicesAndLabor.ToString("c")
lblParts.Text = decPartsCharge.ToString("c")
lblTaxOnParts.Text = decTotalTaxCharges.ToString("c")
lblTotalFees.Text = decTotalCharges.ToString("c")
End Sub
Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
'To clear the controls to default values
ClearOilLube()
ClearFlushes()
ClearMisc()
ClearOther()
End Sub
Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
'Close the form
Close()
End Sub
End Class

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