Day of the week to get the date

I'm a little bit trickery this method, only after 1900-01-01 of data, before the date needs to be recalculated.

1. First remove the number of days from the date of 1900-01-01

        private static int GetDays (int year, int month, Int. day) {//1900-1-1 is Monday int result            = 0;            Int[] month31 = {1,3,5,7,8,10,12};            Int[] month30 = {4,6,9,11};            const int year = 1900;            const int MONTH = 1;            const int day = 1;            The ***************************************** result + = (year-year) * 365 is calculated first for the whole year; for (int i = year, i < year; i++) {if (Isleapyear (i)) {+ +)                Result            }}//Calculate month ******************************************** if (Month > month) {for (int i = month; i < month; i++) {if (i = = 2 &&am P                    Isleapyear (year)) {result + = 29;        } else {result + = 28;            } if (month30.                    Contains (i)) {result + = 30; } if (month31.                    Contains (i)) {result + = 31;                            }}}} else {//month is equal, it is not possible to have a month less than 1, do not need to do any operations, calculate the direct calculation on the following day            }//Calculation day ********************************* result + = Day-day;        return result; }

2, the number of days difference to 7, for example, the difference between 1900-01-07 and 1900-01-01 7 days, then take the remainder to get 0, the explanation is Sunday,

If it is 1900-01-08, then the remainder is 1, and 1900-01-01 is the same as one weeks, i.e. Monday

        <summary>///day of the Week///</summary>//        <param name= "Days" > Day difference </param> //        <param name= "Weekint" > after the remainder </param>//        <returns></returns>        Private static string getweekday (int days,out int weekint)        {            Dictionary<int, string> weekdic = new dictionary< int, string> ();            Weekdic.add (1, "Monday");            Weekdic.add (2, "Tuesday");            Weekdic.add (3, "Wednesday");            Weekdic.add (4, "Thursday");            Weekdic.add (5, "Friday");            Weekdic.add (6, "Saturday");            Weekdic.add (7, "Sunday");            Weekint = days% 7 = = 0? 7:days% 7;            return weekdic[weekint];                    }

3. Output results

                Console.WriteLine ("Please enter a date:");                String datestr = Console.ReadLine ();                string[] Datearray = Datestr.split ('-');                int year = Int. Parse (Datearray[0]);                int month = Int. Parse (datearray[1]);                int day = Int. Parse (datearray[2]);                int days = GetDays (year, month, day);                int weekint = 0;                Console.WriteLine ("Distance 1900-1-1, with" + Days + "Day of the Time");                Console.WriteLine ("This day is" + getweekday (days, out Weekint));

Can be used on the JS calculation week.

Day of the week to get the date