public static void Main(string[] strings)
    {
        MyMoney dm = new MyMoney();

        dm.CurrencyValue = 2.50M;
        Console.WriteLine(dm.CurrencyValue);

        Dollar dollar = new Dollar();

        dollar.InitDollar(1.2M);

        dollar.EuroValue = dm.EuroValue;
        Console.WriteLine(dollar.CurrencyValue);

        dollar.CurrencyValue = 2 * dollar.CurrencyValue;
        dm.EuroValue         = dollar.EuroValue;
        Console.WriteLine(dm.CurrencyValue);
    }