ADT_Stacks.vb

'Task 2.1 Stacks

Module Module1
    Dim StackPtr As Integer
    Dim Stack(0 To 9) As String

    Sub Main()

        StackPtr = 0
        Dim MenuChoice As Integer = 0
        While MenuChoice <> 4
            Console.WriteLine("1. To PUSH to STACK")
            Console.WriteLine("2. To POP from STACK")
            Console.WriteLine("3. Traverse STACK")
            Console.WriteLine("4. To EXIT this module.")
            MenuChoice = Console.ReadLine()
            Select Case MenuChoice
                Case 1 : cmdPush_Click()
                Case 2 : cmdPop_Click()
                Case 3 : cmdTraverse()
                Case 4
                Case Else : Console.WriteLine("Wrong choice. Please try again.")
            End Select
        End While
    End Sub
    Sub cmdPop_Click()
        If StackPtr < 1 Then
            Console.WriteLine("Underflow")
            Exit Sub
        End If
        StackPtr = StackPtr - 1
        Console.WriteLine(Stack(StackPtr))
    End Sub
    Sub cmdPush_Click()
        Dim newVal As String
        Console.WriteLine("Enter new Value: ")
        newVal = Console.ReadLine()
        If StackPtr > 9 Then
            Console.WriteLine("Overflow")
            Exit Sub
        End If
        Stack(StackPtr) = newVal
        StackPtr = StackPtr + 1
    End Sub
    Sub cmdTraverse()
        For count = 9 To 0 Step -1
            Console.WriteLine(Stack(count))
        Next
    End Sub
End Module