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

namespace Rabota_s_array
{
    delegate double Funkcia(double chislo);

    class Program
    {
        static double Raschet(double x)
        {
            return Math.Pow(x, 2) / (2 * x);
        }

        static void Main(string[] args)
        {
            int n;
            do
                Console.Write("Vvedite n=");
            while (!Int32.TryParse(Console.ReadLine(), out n));
            Chislo.funkcia = Raschet;
            List<Chislo> LChislo = new List<Chislo>(n);
            (Enumerable.Range(0, n)).ToList<int>().ForEach(l => LChislo.Add(new Chislo()));
            LChislo.ForEach(l => l.Vyvesti());
            Console.ReadKey();
        }
    }

    class Chislo
    {
        double chislo, resultat;
        public static Funkcia funkcia;
        static int indeks;
        int id;
        public Chislo()
        {
            id = ++indeks;
            bool poschitalo = false;
            do
            {
                do
                    Console.Write("Vvedite x[{0}] = ", indeks);
                while (!Double.TryParse(Console.ReadLine(), out chislo));

                resultat = Schitat();
                poschitalo = !resultat.Equals(Double.NaN);

                if (!poschitalo)
                    Console.WriteLine("Nedopustimyi argument. Povtorite vvod.");
            }
            while (!poschitalo);
        }

        double Schitat()
        {
            return funkcia(chislo);
        }

        public void Vyvesti()
        {
            Console.WriteLine("Chislo: {0}. Resultat: {1:F}", chislo, resultat);
        }
    }
}

 Func<int> readNumber = () =>
            {
                int number;
                while (!int.TryParse(Console.ReadLine(), out number))
                    writeLn("Invalid format, try again");

                return number;
            };

 while (true)
            {
                collectionLength = readNumber();
                const int MAX_LENGTH = 5;
                if (collectionLength > 0 && collectionLength <= MAX_LENGTH)
                    break;

                writeLn(string.Format("Number should be between 0 and {0}. Please try again", MAX_LENGTH));
            }