Subroutine And Function Demo - Console App

'------------------------------------------------------------------------------------------
'           Notice of My Copyright and Intellectual Property Rights
'
' Any intellectual property contained within the program by Joseph L. Bolen remains the
' intellectual property of the Joseph L. Bolen. This means that no person may distribute,
' publish or provide such intellectual property to any other person or entity for any
' reason, commercial or otherwise, without the express written permission of Joseph L. Bolen.
'
'                 Copyright © 2014. All rights reserved.
'        All trademarks remain the property of their respective owners.
'-------------------------------------------------------------------------------------------
' Program Name:   Subroutine And Function Demo - Console App
' Author:         Joseph L. Bolen
' Date Created:   Aug 2014
'
' Description:    Demonstration of a Subroutine and a Function
'
'                 Documentation is at:
'                   App's Visual Basic .NET code is at http://pastebin.com/ZyhdwWV5
'
Module Module1
    Private result As String
    Private aKey As ConsoleKeyInfo

    Sub Main()

        Do
            Console.Clear()

            Dim num1String As String = InputBox("Input first whole number", "Adding Two Numbers", "0")
            If num1String.Length = 0 Then num1String = "0"
            Dim num2String As String = InputBox("Input second whole number", "Adding Two Numbers", "0")
            If num2String.Length = 0 Then num2String = "0"

            ' Call the Subroutine
            AddTwoNumbers(num1String, num2String)
            Console.WriteLine("The sum of " & num1String.Trim & " and " & num2String.Trim & " using a Subroutine is: " & result)

            ' Use the Function
            Console.WriteLine()
            Console.WriteLine("The sum of " & num1String.Trim & " and " & num2String.Trim & " using a Function is: " & AddToNums(num1String, num2String))

            ' Hold console open until key is pressed.
            Console.WriteLine()
            Console.WriteLine("Press the ""Q"" key to end program.")
            aKey = Console.ReadKey()
        Loop While (aKey.Key <> ConsoleKey.Q)

    End Sub

    Private Sub AddTwoNumbers(ByVal pString1 As String, ByVal pString2 As String)
        Dim num1, num2 As Integer
        If Not Integer.TryParse(pString1, num1) Then
            result = vbCrLf & "Error: First value is not a whole number."
            Exit Sub
        End If
        If Not Integer.TryParse(pString2, num2) Then
            result = vbCrLf & "Error: Second value is not a whole number."
            Exit Sub
        End If
        result = (num1 + num2).ToString("n0")
    End Sub

    Private Function AddToNums(ByVal pString1 As String, ByVal pString2 As String) As String
        Dim num1, num2 As Integer
        If Not Integer.TryParse(pString1, num1) Then
            Return vbCrLf & "Error: First value is not a whole number."
        End If
        If Not Integer.TryParse(pString2, num2) Then
            Return vbCrLf & "Error: Second value is not a whole number."
        End If
        Return (num1 + num2).ToString("n0")
    End Function
End Module