using System;

using System.Linq;

public static class DateExtensions

{

    public static DateTime Max(params DateTime[] dates)

        => dates.Max();

​

    public static DateTime Min(params DateTime[] dates)

        => dates.Min();

}

​

    public readonly struct DateRange 

    {

        public DateRange(DateTime from, DateTime to) 

        {

            if (from.Kind != to.Kind) 

            {

                throw new ArgumentException("DateTime args has different Kind");

            }

​

            this.Start = from;

            this.End = to;

        }

​

        public DateTime Start { get; init; }

​

        public DateTime End { get; init; }

    }

​

    public static class DateRangeExtensions 

    {

​

        public static DateRange RangeAscending(this TimeSpan time)

            => new(DateTime.Now.Subtract(time), DateTime.Now);

    }

​

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var range = TimeSpan.FromDays(14).RangeAscending();

        const int daysPortion = 10;

        for (DateTime f = range.Start.Date, t = f.AddDays(daysPortion); t <= range.End.Date; f = f.AddDays(daysPortion), t = DateExtensions.Min(t.AddDays(daysPortion), range.End.Date))

        {

            Console.WriteLine($"{f} ---- {t}");

        }

    }

}