using System;

using System.Diagnostics.Contracts;

​

public class Program {

    public static void Main() {

        short numero = 2017;

        var m = new ShortYear(numero);

        Console.WriteLine(m);

    }

}

//provavelmente teria implemnetações de operadores, outros métodos e das interfaces

//IFormattable, IConvertible, IComparable<ShortYear>, IEquatable<ShortYear> e outras

public struct ShortYear {

    public byte Year;

    public const short Century = 1900;

    public ShortYear(short value) {

        Contract.Ensures(value >= Century && value < Century + 256);

        Year = (byte)(value - Century);

    }

    public ShortYear(int value) {

        Contract.Ensures(value >= Century && value < Century + 256);

        Year = (byte)(value - Century);

    }

    public static implicit operator short(ShortYear value) => (short)(value.Year + Century);

    public static implicit operator int(ShortYear value) => value.Year + Century;

    public override int GetHashCode() => Year.GetHashCode();

    public override String ToString() => (Year + Century).ToString();

}

​