Imports System

Module Module1

Public Sub Main()
    Try 
        Dim guest1 As Guest = New Guest("Ben", "Miller", 17)
        Console.WriteLine(guest1.GuestInfo)
    Catch outOfRange As Exception
        Console.WriteLine("Error: {0}", outOfRange.Message)
    End Try 
End Sub 

Class Guest

    Private FirstName As String 
    Private LastName As String 

    Private Age As Integer 

    Public Sub New(ByVal fName As String, ByVal lName As String, ByVal age As Integer)
        MyBase.New()
        FirstName = fName
        LastName = lName
        If (age < 21) Then 
            Throw New ArgumentOutOfRangeException("age", "All guests must be 21-years-old or older.")
        Else
            age = age
        End If 
    End Sub 

    Public Function GuestInfo() As String 
        Dim gInfo As String = (FirstName + (" " _
                    + (Me.LastName + (", " + Me.Age.ToString))))
        Return gInfo
    End Function 
End Class 

End Module

using System;

class Program
{
    static void Main(string[] args)
    {
        try
        {
            Guest guest1 = new Guest("Ben", "Miller", 17);
            Console.WriteLine(guest1.GuestInfo());
        }
        catch (ArgumentOutOfRangeException outOfRange)
        {

            Console.WriteLine("Error: {0}", outOfRange.Message);
        }
    }
}

class Guest
{
    private string FirstName;
    private string LastName;
    private int Age;

    public Guest(string fName, string lName, int age)
    {
        FirstName = fName;
        LastName = lName;
        if (age < 21)
            throw new ArgumentOutOfRangeException("age","All guests must be 21-years-old or older.");
        else
            Age = age;
    }

    public string GuestInfo()
    {
        string gInfo = FirstName + " " + LastName + ", " + Age.ToString();
        return(gInfo);
    }
}