using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

namespace PrimesInGivenRange

{

    public class Program

    {

        static bool IsPrime(long n)

        {

            if (n < 2)

            {

                return false;

            }

            else

            {

                for (int i = 2; i <= Math.Sqrt(n); i++)

                {

                    if (n % i == 0) return false;

                }

            }

            return true;

        }

​

        static List<int> FindPrimesInRange(int startNum, int endNum)

        {

            List<int> primeNumbers = new List<int> { };

            int length = 0;

            if (startNum > endNum)

            {

                Console.WriteLine("(empty list)");

            }

            else

            {

                for (int i = startNum; i <= endNum; i++)

                {

                    if (Program.IsPrime(i))

                    {

                        primeNumbers.Add(i);

                        length++;

                    }

                }

            }

            return primeNumbers;

        }

​

        public static void Main()

        {

            Console.WriteLine("Program that calculates all prime numbers in given range and returns them as list of integers.");

            Console.WriteLine("Write number to start the range");

            int start = int.Parse(Console.ReadLine());

            Console.WriteLine("Write number to end the range");

            int end = int.Parse(Console.ReadLine());

            List<int> range = Program.FindPrimesInRange(start, end);

            Console.WriteLine("The prime numbers between {0} and {1} are:", start, end);

            range.ForEach(Console.WriteLine);

        }

    }

}

​