Modify your project from step 2 to use a function to do range checks. For retail price the range is from $9.99 to $1,999.99 and discount should be from one to ten percent. I will attached the program interface

This is the code I use un program :

Public Class Form1 Private decRetail As Decimal ' To hold the retail price Private decPercentage As Decimal ' To hold the discount percentage

Private Function ValidateInputFields() As Boolean 'Try to convert each of the input fields. Return False if 'any field is invalid, and display a suitable error message.

If Not Decimal.TryParse(txtRetailPrice.Text, decRetail) Then lblMessage.Text = "Retail price must be numeric" Return False End If

If Not Decimal.TryParse(txtDiscountPercent.Text, decPercentage) Then lblMessage.Text = "Discount percentage must be numeric"

Return False End If

Return True End Function Function CalculateSalePrice(ByVal decRetail As Decimal, ByVal decPercentage As Decimal) As Decimal ' Calculate and return the sale price. Dim decSalePrice As Decimal

decSalePrice = decRetail - (decRetail * decPercentage) Return decSalePrice End Function

Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click Dim decSalePrice As Decimal

' Clear any previous message. lblMessage.Text = String.Empty

' If the input is valid, display the sale price. If ValidateInputFields() Then decSalePrice = CalculateSalePrice(decRetail, decPercentage) txtSalePrice.Text = decSalePrice.ToString("c") End If

End Sub

Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click Me.Close() End Sub End Class

Form1 Retail Price: Discount Percentage: Sale Price: Calculate Sale Price Exit