vb.vb

' Imports System.Collections.Generic
Module Vec
    Public Class Vector
        Protected _v As Double()

        Public Sub New(
            ByVal ParamArray elements _
            As Double()
        )
            MyClass._v = elements : End Sub

        Public Sub New(
            ByVal initArr As Double()
        )
            MyClass._v = initArr : End Sub

        NotOverridable Public ReadOnly Property Elements() As Double()
            Get : Return MyClass._v : End Get : End Property

        NotOverridable Public ReadOnly Property Length() As Long
            Get : Return UBound(
                MyClass._v,
            1) + 1 : End Get : End Property

        Public Shared Operator + (
            ByVal a As Vector,
            ByVal b As Vector
        ) As Vector
            Try
                Dim tmp(a.Length - 1) As Double
                For i As Integer = 0 To a.Length - 1
                    tmp(i) =  _
                        a.elements(i) + _
                        b.elements(i) : Next i

                Return New Vector(tmp)
            Catch _err As System.IndexOutOfRangeException
                Throw New System _
                    .Exception(
                        "two vectors must have same length"
                    )
            Catch err As Exception
                Throw err
            End Try
        End Operator

    End Class

    Public Class Vector2D : Inherits Vector
        Public Sub New(
            ByVal x As Double,
            ByVal y As Double
        )
            Dim arr2(1) As Double
            arr2(0) = x : arr2(1) = y

            MyClass._v = arr2
        End Sub

        Public Property x() As Double
            Get : Return _v(0) : End Get 
            Set(ByVal newX As Double)
                _v(0) = newX : End Set
        End Property

        Public Property y() As Double
            Get : Return _v(1) : End Get 
            Set(ByVal newY As Double)
                _v(1) = newY : End Set
        End Property

        Public Shared Operator + (
            ByVal a As Vector2D,
            ByVal b As Vector2D
        ) As Vector2D
            Return New Vector2D(
                a.x + b.x,
                a.y + b.y
            ) : End Operator
    End Class

    Public Class Box
        Private _w As Double
        Private _h As Double

        Public Sub New(
            ByVal width As Double,
            ByVal height As Double
        )
            MyClass._w = width : MyClass._h = height
        End Sub

        NotOverridable Public ReadOnly Property Width() As Double
            Get : Return _w : End Get : End Property

        NotOverridable Public ReadOnly Property Height() As Double
            Get : Return _h : End Get : End Property

        Public Sub SetWidth(
            ByVal width As Double
        )
            MyClass._w = width : End Sub

        Public Sub SetHeight(
            ByVal height As Double
        )
            MyClass._h = height : End Sub
        
    End Class

    Public Class Style
        Public Color As String
    End Class

    Public Interface IDrawable
        Function Move()
    End Interface

    Public Class Pos
        Public x As Double
        Public y As Double
    End Class

    Public Class Ball : Implements IDrawable
        Public Function Move() Implements IDrawable.Move
        End Function
        
        Public pos As Pos
    End Class

End Module

Module mainModule
    Public Function Main(
        ByVal args As String()
    ) As Integer

        Dim v As New Vector2D(10, 20)
        Dim v2 As New Vector2D(30, 40)

        ' For Each el As Double In (v + v2).Elements
        '     Console.WriteLine(el)
        ' Next


        Return 0 : End Function
End Module