using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        var startDate = new DateTime(2018, 11, 1);

        var endDate = new DateTime(2018, 12, 31);

​

        int diff = (7 + (startDate.DayOfWeek - DayOfWeek.Monday)) % 7;

        var weekStartDate = startDate.AddDays(-1 * diff).Date;

        var i = 1;

        var weekEndDate = DateTime.MinValue;    

        while(weekEndDate < endDate) {

            weekEndDate = weekStartDate.AddDays(6);

            var shownStartDate = weekStartDate < startDate ? startDate : weekStartDate;

            var shownEndDate = weekEndDate > endDate ? endDate : weekEndDate;

            Console.WriteLine($"Week {i++}: {shownStartDate:dd MMMM yyyy} - {shownEndDate:dd MMMM yyyy}");

            weekStartDate = weekStartDate.AddDays(7);

        }

    }

}