Table + coffetable + leg Learn programming Visual Basic (VB.net)

Lesson:

More On Classes


Exercise:

Table + coffetable + leg 7


Objetive:

Extend the example of the tables and the coffee tables, to add a class "Leg" with a method "ShowData", which will write "I am a leg" and then it will display the data of the table to which it belongs.

Choose one table in the example, add a leg to it and ask that leg to display its data.


Code:

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Namespace Tables
    Class CoffeeTable
        Inherits Table

        Public Sub New(ByVal tableWidth As Integer, ByVal tableHeight As Integer)
            MyBase.New(tableWidth, tableHeight)
        End Sub

        Public Overrides Sub ShowData()
            Console.WriteLine("Width: {0}, Height: {1}", width, height)
            Console.WriteLine("(Coffee table)")
        End Sub
    End Class
End Namespace

Namespace Tables
    Class Leg
        Private myTable As Table

        Public Sub New()
        End Sub

        Public Sub SetTable(ByVal t As Table)
            myTable = t
        End Sub

        Public Sub ShowData()
            Console.WriteLine("I am a leg")
            myTable.ShowData()
        End Sub
    End Class
End Namespace

Namespace Tables
    Class Table
        Protected width, height As Integer
        Protected myLeg As Leg

        Public Sub New(ByVal tableWidth As Integer, ByVal tableHeight As Integer)
            width = tableWidth
            height = tableHeight
        End Sub

        Public Sub AddLeg(ByVal l As Leg)
            myLeg = l
            myLeg.SetTable(Me)
        End Sub

        Public Overridable Sub ShowData()
            Console.WriteLine("Width: {0}, Height: {1}", width, height)
        End Sub
    End Class
End Namespace

Namespace Tables
    Class TestTable
        Private Shared Sub Main(ByVal args As String())
            Dim t As Table = New Table(80, 120)
            Dim l As Leg = New Leg()
            t.AddLeg(l)
            l.ShowData()
            Console.WriteLine()
            Dim tableList As Table() = New Table(9) {}
            Dim random As Random = New Random()

            For i As Integer = 0 To tableList.Length - 1

                If i < tableList.Length / 2 Then
                    tableList(i) = New Table(random.[Next](50, 201), random.[Next](50, 201))
                Else
                    tableList(i) = New CoffeeTable(random.[Next](40, 121), random.[Next](40, 121))
                End If
            Next

            For i As Integer = 0 To tableList.Length - 1
                tableList(i).ShowData()
            Next

            Console.ReadLine()
        End Sub
    End Class
End Namespace