Imports System

Public Module Stack

    Sub Main()

        InitializeStack()

        Dim Choice As Integer = 0

        While Choice <> 4

            Console.WriteLine("1 - Insert New Item")

            Console.WriteLine("2 - Delete An Item")

            Console.WriteLine("3 - Print")

            Console.WriteLine("4 - Exit")

            Choice = Console.ReadLine

            Select Case Choice

                Case 1 'insert

                    Console.WriteLine("Input the number you want to insert")

                    Dim NewItem As Integer

                    NewItem = Console.ReadLine()

                    Insert(NewItem)

                Case 2 'Search  

                Console.WriteLine("Input the number you want to delete")

                    Dim DeleteItem As Integer

                    DeleteItem = Console.ReadLine()

                    Delete(DeleteItem)

                Case 3 'Print 

                PrintStack()

            End Select

        End While

    End Sub

    Const NULLPOINTER As integer = -1

    Dim BaseOfStackPointer As Integer = 0

    Dim TopOfStackPointer As Integer = -1

    Dim Stack(8) As Integer

    Sub InitializeStack()

        For i = 0 To 7

            Stack(i) = NULLPOINTER

        Next

    End Sub

​

    Sub Insert(NewItem)

        If TopOfStackPointer < Stack.Length

            TopOfStackPointer += 1

            Stack(TopOfStackPointer) = NewItem

        End If

    End Sub

​

    Sub Delete(DeleteItem)

        'search for item

        For i = BaseOfStackPointer To TopOfStackPointer

        If Stack(i) = DeleteItem Then

            For j = i To TopOfStackPointer - 1

                Stack(j) = Stack(j+1)

            Next

            Stack(TopOfStackPointer) = NULLPOINTER

            TopOfStackPointer -=1

        End If

        Next

    End Sub

​

    Sub PrintStack()

        For i = BaseOfStackPointer To TopOfStackPointer

            Console.WriteLine(i & " " & Stack(i))

        Next

End Sub

​

End Module