using System;

public class Program

{

    public struct Building {

        int _number;

        string _address;

        string _description;

        public Building(int number, string address, string description = null) {    

            _number = number;

            _address = address;

            _description = description;

        }

        public string Address {get{ return _address;} set { _address = value;}}

        public string Description {get{ return _description;} set { _description = value;}}

    }

​

    public static void Main()

    {

        var build1 = new Building(42, "Awesome St, 42", "good company");

        var build2 = new Building(42, "Awesome St, 42", "bad company");

        PrintInfo(build1); // ???

        PrintInfo(build2); // ???

    }

​

    public static void PrintInfo(Building build){

        Console.WriteLine("{0} : {1} ({2})", build.GetHashCode(), build.Address, build.Description);

    }

}