практикум 14 задание I

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

namespace ConsoleApp1
{

    static class GlobalVar
    {
        static public double R;
    }
    struct SPoint : IComparable<SPoint>
    {


        public int x, y;
        private int countOfPoint;
        static private double R;
        public SPoint(int x, int y)
        {
            this.x = x; this.y = y;
            countOfPoint = 0;

            R = GlobalVar.R;
        }

        static public void calculate(SPoint[] a)
        {
            for (int j = 0; j < a.Length; ++j)
            {
                ref SPoint cur = ref a[j];
                for (int i = 0; i < a.Length; ++i)
                    if (Distance(cur, a[i]) <= R)
                        cur.countOfPoint++;
            }
        }
        public void Show()
        {
            Console.WriteLine("({0}, {1})", x, y);
        }
        static private double sqr(double a)
        {
            return a * a;
        }
        static public double Distance(SPoint a, SPoint b)
        {
            return Math.Sqrt(sqr(a.x - b.x) + sqr(a.y - b.y));
        }
        public int CompareTo(SPoint obj)
        {

            if (this.countOfPoint == obj.countOfPoint)
            {
                return 0;
            }
            else
            {
                if (this.countOfPoint > obj.countOfPoint)
                {
                    return 1;
                }

                else
                {
                    return -1;
                }
            }
        }
    }
    class Program
    {


        static void Print(SPoint[] array) //выводим данные на экран
        {
            foreach (SPoint item in array)
            {
                item.Show();
            }
        }

        static void Main()
        {
            using (StreamReader file = new StreamReader("d:/input.txt"))
            {
                int n = Int32.Parse(file.ReadLine());
                GlobalVar.R = Double.Parse(file.ReadLine());
                SPoint[] a = new SPoint[n];
                for (int i = 0; i < n; ++i)
                {
                    int x, y;
                    string [] line = file.ReadLine().Split();
                    x = int.Parse(line[0]);
                    y = int.Parse(line[1]);
                    a[i] = new SPoint(x, y);
                }
                SPoint.calculate(a);
                Array.Sort(a); //Вызов стандартной сортировки для класса Array
                Console.WriteLine("Упорядоченные данные: ");
                Print(a);
            }
        }
    }
}