Klassen, Vererbung und Interfaces

Public Class Person
    Public Property Name As String
    Public Property Alter As Integer
    Private _geheim As Integer = 42

    Public Sub New(name As String, alter As Integer)
        Me.Name = name
        Me.Alter = alter
    End Sub

    Public Function IstVolljaehrig() As Boolean
        Return Alter >= 18
    End Function

    Public Overrides Function ToString() As String
        Return $"{Name} ({Alter})"
    End Function

    Public Shared Function Kind(name As String) As Person
        Return New Person(name, 5)
    End Function
End Class

Module Program
    Sub Main()
        Dim p As New Person("Mia", 17)
        Console.WriteLine(p)
        p.Alter = 18
        Console.WriteLine(p.IstVolljaehrig())
        Console.WriteLine(Person.Kind("Ben"))
        Dim q = New Person("Tom", 25) With {.Alter = 26}
        Console.WriteLine(q)
        Console.WriteLine(p Is q)
        Console.WriteLine(p.Equals(p))
    End Sub
End Module

Public MustInherit Class Tier
    Public ReadOnly Property Name As String

    Public Sub New(name As String)
        Me.Name = name
    End Sub

    Public Overridable Function Laut() As String
        Return "..."
    End Function

    Public Function Vorstellen() As String
        Return Name & " sagt " & Laut()
    End Function
End Class

Public Class Hund
    Inherits Tier
    Public Sub New(name As String)
        MyBase.New(name)
    End Sub
    Public Overrides Function Laut() As String
        Return "Wau"
    End Function
End Class

Public Class Katze
    Inherits Tier
    Public Sub New(name As String)
        MyBase.New(name)
    End Sub
    Public Overrides Function Laut() As String
        Return "Miau"
    End Function
End Class

Module Program
    Sub Main()
        Dim tiere As Tier() = {New Hund("Rex"), New Katze("Mimi")}
        For Each t In tiere
            Console.WriteLine(t.Vorstellen())
        Next
        Console.WriteLine(TypeOf tiere(0) Is Hund)
        Console.WriteLine(TypeOf tiere(1) Is Hund)
        Dim h As Hund = TryCast(tiere(0), Hund)
        Console.WriteLine(h IsNot Nothing)
        Console.WriteLine(tiere(1).GetType().Name)
    End Sub
End Module

Public Interface IFlaeche
    Function Flaeche() As Double
End Interface

Public Class Kreis
    Implements IFlaeche
    Private ReadOnly r As Double
    Public Sub New(r As Double)
        Me.r = r
    End Sub
    Public Function Flaeche() As Double Implements IFlaeche.Flaeche
        Return Math.PI * r * r
    End Function
End Class

Public Class Rechteck
    Implements IFlaeche
    Private ReadOnly b, h As Double
    Public Sub New(b As Double, h As Double)
        Me.b = b : Me.h = h
    End Sub
    Public Function Flaeche() As Double Implements IFlaeche.Flaeche
        Return b * h
    End Function
End Class

Public Structure Punkt
    Public X As Integer
    Public Y As Integer
    Public Sub New(x As Integer, y As Integer)
        Me.X = x : Me.Y = y
    End Sub
    Public Overrides Function ToString() As String
        Return $"({X}, {Y})"
    End Function
End Structure

Public Enum Wochentag
    Montag = 1
    Dienstag
    Mittwoch
End Enum

Module Program
    Sub Main()
        Dim formen As IFlaeche() = {New Kreis(1.0), New Rechteck(3.0, 4.0)}
        For Each f In formen
            Console.WriteLine(f.Flaeche().ToString("F2"))
        Next
        Dim p As New Punkt(3, 4)
        Dim q = p
        q.X = 99
        Console.WriteLine(p.ToString() & " " & q.ToString())
        Console.WriteLine(Wochentag.Dienstag & " " & CInt(Wochentag.Mittwoch) & " " & [Enum].GetName(GetType(Wochentag), 1))
    End Sub
End Module

Public Class Thermostat
    Private _temperatur As Double
    Public Event Ueberhitzt(grad As Double)

    Public Property Temperatur As Double
        Get
            Return _temperatur
        End Get
        Set(value As Double)
            _temperatur = value
            If value > 100 Then RaiseEvent Ueberhitzt(value)
        End Set
    End Property
End Class

Module Program
    Private WithEvents Messgeraet As New Thermostat()

    Private Sub Alarm(grad As Double) Handles Messgeraet.Ueberhitzt
        Console.WriteLine($"ALARM: {grad} Grad")
    End Sub

    Sub Main()
        Messgeraet.Temperatur = 50
        Messgeraet.Temperatur = 120

        Dim t As New Thermostat()
        AddHandler t.Ueberhitzt, Sub(g) Console.WriteLine("Lambda-Handler: " & g)
        t.Temperatur = 200

        Dim op As Func(Of Integer, Integer, Integer) = Function(a, b) a + b
        Dim aktion As Action(Of String) = Sub(s) Console.WriteLine("Aktion: " & s)
        aktion(op(3, 4).ToString())
    End Sub
End Module