Imports System

' This Person class has Name and Age fields.
Public Class Person
    Public Property Name As String
    Public Property Age As Integer

    ' Constructor to initialize a new Person with the given name.
    Public Sub New(name As String)
        Me.Name = name
        Me.Age = 42 ' Default age for the example
    End Sub

    ' Overriding the ToString method for a custom display format.
    Public Overrides Function ToString() As String
        Return $"{Name} {Age}"
    End Function
End Class

Module Program
    Sub Main()
        ' This syntax creates a new class instance.
        Console.WriteLine(New Person("Bob") With {.Age = 20}.ToString())

        ' You can name the fields when initializing a class instance.
        Console.WriteLine(New Person("Alice") With {.Age = 30}.ToString())

        ' Omitted fields will have their default values.
        Console.WriteLine(New Person("Fred").ToString())

        ' Getting a reference to the class instance.
        Dim ann As New Person("Ann") With {.Age = 40}
        Console.WriteLine(ann.ToString())

        ' Encapsulating new class creation in a function
        Console.WriteLine(NewPerson("Jon").ToString())

        ' Access class fields with a dot.
        Dim sean As New Person("Sean") With {.Age = 50}
        Console.WriteLine(sean.Name)

        ' You can also use dots with class references - no dereferencing needed.
        Dim sp As Person = sean
        Console.WriteLine(sp.Age)

        ' Class instances are mutable.
        sp.Age = 51
        Console.WriteLine(sp.Age)

        ' Using an anonymous class for temporary data structures.
        Dim dog = New With {.Name = "Rex", .IsGood = True}
        Console.WriteLine(dog.ToString())
    End Sub

    ' Function to construct a new Person instance with a given name.
    Function NewPerson(name As String) As Person
        Dim p As New Person(name)
        p.Age = 42
        Return p
    End Function
End Module