knax

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            NouvelOperateur();
        }
        private static void NouvelOperateur()
        {
            //Nouvel operateur en c# , ? , permet de declarer des variable nullable

            string server1 = null;
            string server2 = null;
            string defaut = "127.0.0.1";

            //Affichera 127.0.0.1
            Console.WriteLine(server1 ?? server2 ?? defaut);

            server1 = "192.168.1.100";
            server2 = "192.168.1.101";
            defaut = "127.0.0.1";

            //Affichera 192.168.1.100
            Console.WriteLine(server1 ?? server2 ?? defaut);

            server1 = null;
            server2 = null;
            defaut = null;

            //Affiche rien
            Console.WriteLine(server1 ?? server2 ?? defaut);

            int? int1 = null;
            bool? bool1 = null;
            string? str = null;
            double? dbl = null;
            long? lng = null;
            //etc ...

           
            
            Console.ReadLine();

        }
    }
}