MyDateClass

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp9
{

    class MyData
    {
        int[] datearr = { 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 303, 334 };
        public enum Days { Sunday, Monday, Tuesday, Wensday, Thursday, Friday, Sataday };
        int day;
        public int Day { get; }
        int mounth;
        public int Mounth { get; }
        int year;
        public int Year { get; }


        public MyData(int year, int mounth, int day)
        {
            this.year = year;
            this.mounth = mounth;
            this.day = day;

        }

        public MyData()
        {
            this.year = 1;
            this.mounth = 1;
            this.day = 1;
        }

        public Days WhatDay()

        {
            int a = (14 - mounth) / 12;
            int y = year - a;
            int m = mounth + 12 * a - 2;
            int result = (day + y + y / 4 - y / 100 + y / 400 + (31 * m) / 12) % 7;
            Days weakDay = (Days)result;
            return weakDay;

        }
        static bool IsYearLeap(int year)
        {
            if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
                return true;
            else
                return false;
        }

        public int NumberOfLeapYears(int year)
        {
            int counter = 0;

            for (int years = 0; years <= year; years++)
                counter += MyData.IsYearLeap(years) ? 1 : 0;

            return counter;
        }

        public int NumberOfDays()
        {
            int days;
            if (this.mounth > 2)
            {
                days = NumberOfLeapYears(this.year - 1);
            }
            else
            {
                days = NumberOfLeapYears(this.year);
            }
            days += 365 * (this.year - 1);
            days += datearr[this.mounth];
            days += this.day;
            return days;
        }
        private int DayInMonths(int month, int year)
        {
            int[] days = new int[12] { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
            if (IsYearLeap(year))
                days[1] = 29;
            return days[month - 1];
        }

        public MyData(int days)
        {

            if (day < 0)
                throw new Exception("InvalidDataExeption.DataOutOfRange");
            else
            {
                int years = 0;
                int i = days;
                int month = 0;
                int countLeapYear = 0;
                do
                {
                    if (IsYearLeap(years))
                    {
                        i -= 366;
                        countLeapYear++;
                    }
                    else
                        i -= 365;
                    years++;
                } while (i > 1);

                int lostDays = days - ((years - 1) * 365 + countLeapYear);
                for (month = 1; lostDays > DayInMonths(month, years); month++)
                {
                    lostDays -= DayInMonths(month, years);
                }
                day = lostDays;
                this.mounth = month;
                year = years;
            }




        }

        public static int operator - (MyData date, MyData other)
        {
            int sumOfDaysDate = date.NumberOfDays();
            int sumOfDaysOther = other.NumberOfDays();
            return sumOfDaysDate - sumOfDaysOther;
        }

        public static MyData operator + (MyData date, int days)
        {
            int sumOfDays = date.NumberOfDays() + days;
             MyData newdate = new MyData(sumOfDays);
            return newdate;
        }

        public static MyData operator ++ (MyData date)
        {
            int days = date.NumberOfDays();
                days++;
            MyData newdate = new MyData(days);
            return newdate;

        }
        public static MyData operator --(MyData date)
        {
            int days = date.NumberOfDays();
            days--;
            MyData newdate = new MyData(days);
            return newdate;

        }

        public static bool operator > (MyData date, MyData other)
        {
            int myDate = date.NumberOfDays();
            int otherDate = other.NumberOfDays();
            return myDate > otherDate;

        }
        public static bool operator <(MyData date, MyData other)
        {
            int myDate = date.NumberOfDays();
            int otherDate = other.NumberOfDays();
            return myDate < otherDate;

        }


        public static bool operator == (MyData date, MyData other)
        {
            int myDate = date.NumberOfDays();
            int otherDate = other.NumberOfDays();
            return myDate == otherDate;

        }
        public static bool operator !=(MyData date, MyData other)
        {
            int myDate = date.NumberOfDays();
            int otherDate = other.NumberOfDays();
            return myDate != otherDate;


        }
        public override string ToString()
        {
            return $"{day}, {mounth}, {year}, {WhatDay()};";
        }
    }
    class Program
    {


        static void Main(string[] args)
        {
            MyData calendar = new MyData(2019, 4, 27);
            Console.WriteLine(calendar.ToString());
            Console.WriteLine(calendar.NumberOfDays());

        }
    }
}