Public Class frmFurniture

    Private Sub btnProcess_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnProcess.Click
        Dim Name, Address, Zip As String, Chairs, Sofas As Double
        Name = txtName.Text
        Address = txtAddress.Text
        Zip = txtZip.Text
        Chairs = CDbl(txtChairs.Text)
        Sofas = CDbl(txtSofas.Text)
        Invoice(Name, Address, Zip, Chairs, Sofas)

    End Sub
    Sub Invoice(ByRef Name As String, ByVal address As String, ByVal zip As String, ByVal chairs As Double, ByVal sofas As Double)
        Dim Invoice As String, SofaPrice, ChairPrice, Tax As Double
        Dim sr As IO.StreamReader = IO.File.OpenText("PRICE_TAXDATA.TXT")
        Dim fmtstr As String = "{0,12}|{1,10}"
        Dim basePrice, total As Double
        Invoice = InvoiceNum(Name, zip)
        ChairPrice = CDbl(sr.ReadLine)
        SofaPrice = CDbl(sr.ReadLine)
        Tax = CDbl(sr.ReadLine)
        basePrice = (ChairPrice * chairs) + (SofaPrice * sofas)
        total = (basePrice * Tax) + basePrice
        lstDisplay.Items.Add("Invoice Number: " & InvoiceNum(Name, zip))
        lstDisplay.Items.Add("")
        lstDisplay.Items.Add("Name: " & NameSwitch(Name))
        lstDisplay.Items.Add("Address: " & address)
        lstDisplay.Items.Add("City: " & zip)
        lstDisplay.Items.Add("")
        lstDisplay.Items.Add("Number of chairs: " & chairs)
        lstDisplay.Items.Add("Number of sofas: " & sofas)
        lstDisplay.Items.Add("")
        lstDisplay.Items.Add(String.Format(fmtstr, "Cost:", FormatCurrency(basePrice)))
        lstDisplay.Items.Add(String.Format(fmtstr, "Sales Tax", FormatCurrency(basePrice * Tax)))
        lstDisplay.Items.Add(String.Format(fmtstr, " ", "-----------"))
        lstDisplay.Items.Add(String.Format(fmtstr, "Total Cost:", FormatCurrency(total)))
    End Sub
    Function InvoiceNum(ByVal name As String, ByVal zip As String) As String
        Dim letterName = name.Substring(0, 2).ToUpper
        Dim numZip = zip.Substring(zip.Length - 5)
        Dim invoiceNumber As String
        invoiceNumber = letterName & numZip
        Return (invoiceNumber)
    End Function
    Public Function NameSwitch(ByVal name As String) As String
        Dim names = name.Split(","c)
        Dim firstName = names(1).Trim()
        Dim lastName = names(0).Trim()
        Return firstName + " " + lastName
    End Function

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
        txtAddress.Clear()
        txtChairs.Clear()
        txtName.Clear()
        txtSofas.Clear()
        txtZip.Clear()
        lstDisplay.Items.Clear()
    End Sub

    Private Sub btnQuit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnQuit.Click
        Application.Exit()
    End Sub
End Class