namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            WeekClass week0 = new WeekClass() { day="Monday"};
            WeekClass week1 = new WeekClass() { day="Monday"};
            WeekClass week2 = week0;

            setTuesday(week0);
            setTuesday(week1.day);

            Console.WriteLine(week0);  //Output: ???
            Console.WriteLine(week1);  //Output: ???
            Console.WriteLine(week2);  //Output: ???
            Console.ReadLine();
        }

        public static void  setTuesday(WeekClass weekClass)
        {
            weekClass.day = "Tuesday";
        }

        public static void setTuesday(string day)
        {
            day = "Tuesday";
        }

        public class WeekClass
        {
            public string day;

            public override string ToString()
            {
                return day.ToString();
            }
        }
    }
}