using System;

​

namespace primeNumberProgram

{

    /// <summary>

    ///  By default <c>Program</c> class is main entry of the project for console applications.

    /// </summary>

    public class Program

    {

        /// <summary>

        /// Default constructor for <c>Program</c> class.

        /// </summary>

        protected Program()

        {

        }

​

        /// <summary>

        /// In console applications program control looks for static void main.

        /// </summary>

        /// <param name="args">

        /// Arguments to main from properties debug command line arguments.

        /// </param>

        public static void Main(string[] args)

        {

            Console.WriteLine("Please eneter a number greater than 2 and not greater than 100.");

            ushort inputNumber = 0;

            while (!UInt16.TryParse(Console.ReadLine(), out inputNumber) || inputNumber < 2 || inputNumber > 100)

            {

                Console.WriteLine("Given input is invalid. It should be a valid number greater than 2 and not greater than 100.");

            }

​

            Program p = new Program();

            p.PrintPrimeNumbers(2, inputNumber);

            Console.WriteLine("Press any key to exit");

            Console.ReadKey();

        }

​

        /// <summary>

        /// Method prints all prime numbers between given two positive numbers.

        /// </summary>

        /// <param name="lowerLimit">

        /// Lower limit for all prime numbers.

        /// </param>

        /// <param name="upperLimit">

        /// upper limit for all prime numbers.

        /// </param>

        /// <exception cref="System.OverflowException">

        /// Throws exception when any of parameter is less than

        /// <see cref="UInt16.MinValue">MinValue</see> and greater than  

        /// <see cref="UInt16.MaxValue">MaxValue</see>

        /// Reference can be found here.

        /// <see href="https://docs.microsoft.com/dotnet/api/system.uint16.maxvalue"/>

        /// </exception>

        private void PrintPrimeNumbers(ushort lowerLimit, ushort upperLimit)

        {

            lowerLimit++;

            bool foundPrime = false;

            while (lowerLimit < upperLimit)

            {

                if (IsPrime(lowerLimit))

                {

                    if (!foundPrime)

                    {

                        Console.WriteLine("Prime numbers");

                        foundPrime = true;

                    }

                    Console.Write(lowerLimit + "\n");

                }

                lowerLimit++;

            }

​

            if (!foundPrime)

            {

                Console.WriteLine("No prime mumber exsits.");

            }

        }

​

        /// <summary>

        ///  Method to check if given number is prime or not.

        /// </summary>

        /// <returns>

        ///  Returns true if number is prime otherwise false.

        /// </returns>

        /// <param name="number">

        ///  Takes a positive integer number.

        /// </param>

        /// <exception cref="System.OverflowException">

        ///  Throws exception when any of parameter is less than

        /// <see cref="UInt16.MinValue">MinValue</see> and greater than  

        /// <see cref="UInt16.MaxValue">MaxValue</see>

        ///  Reference can be found here. 

        /// <see href="https://docs.microsoft.com/dotnet/api/system.uint16.maxvalue"/>

        /// </exception>

        private bool IsPrime(ushort number)

        {

            short limit = (short)Math.Sqrt(Convert.ToDouble(number));

            Int128 i = 0;

            if (number % 2 == 0)

            {

                i = 2;

            }

            else

            {

                i = 3;

            }

​

            while (i <= limit)

            {

                if (number % i == 0)

                {

                    return false;

                }

                i += 2;

            }

​

            return true;

        }

    }

}