p1.cs

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

namespace ConsoleApplication3
{
    class My
    {
        public static void Main()
        {
            MyPoint n = new MyPoint { X = 1, Y = 2, Z = 3 };
            MyPoint l = new MyPoint { X = 2, Y = 3, Z = 4 };
            //if (n.CompareTo(l) )
            
            l.FillArray(5);
            MyPoint[] arr = l.GetArr();
            Array.Sort(arr, MyPoint.SortByX);

            foreach(var i in arr)
                Console.WriteLine(i.X);

            Console.WriteLine("\nSECOND FASE : ITERATORS");
            Console.WriteLine(l[1]);
            l[1] = new MyPoint { X = 2, Y = 3, Z = 4 };
            Console.WriteLine(l[1]);

            Console.WriteLine(l["second"]);


            Console.WriteLine("\nSECOND FASE : OPETORS OVERLOADING");
            Console.WriteLine(n + l);
            Console.WriteLine(n + 123);

            Console.Read();
        }
    }

    class MyPoint : IEnumerable, ICloneable, IComparable
    {
        int x;
        int y;
        int z;

        MyPoint[] arr;

        public int X
        {
            get { return x;  }
            set { x = value; }
        }

        public int Y
        {
            get { return y; }
            set { y = value; }
        }

        public int Z
        {
            get { return z; }
            set { z = value; }
        }

        public static IComparer SortByX
        {
            get
            {
                return (IComparer)new PointComparer();
            }
        }

        public MyPoint()
        {
            Random r = new Random();
            x = r.Next(1, 101);
            y = r.Next(1, 101);
            z = r.Next(1, 101);
        }

        public MyPoint this[int index]
        {
            get
            {
                if (arr == null)
                {
                    Console.WriteLine("Empty!");
                    return null;
                }
                return arr[index];
            }

            set
            {
                if (arr == null)
                {
                    Console.WriteLine("Empty");
                }
                else
                {
                    arr[index] = value;
                }
            }
        }

        public MyPoint this[string s]
        {
            get
            {
                if (arr == null)
                {
                    Console.WriteLine("Empty!");
                    return null;
                }
                if (s == "first")
                    return arr[1];
                else if (s == "second")
                    return arr[2];
                return new MyPoint();
            }

            set
            {
                if (arr == null)
                {
                    Console.WriteLine("Empty");
                }
                else
                {
                    if (s == "first")
                        arr[1] = value;
                    else if (s == "second")
                        arr[2] = value;
                }
            }
        }

        public MyPoint[] GetArr()
        {
            return arr;
        }

        public MyPoint(int x, int y, int z)
        {
            X = x;
            Y = y;
            Z = z;
        }

        public int CompareTo(object o)
        {
            MyPoint p = o as MyPoint;
            if (p != null)
            {
                if (this.X > p.X)
                {
                    return -1;
                }
                else
                {
                    if (this.X > p.X)
                        return 1;
                    else 
                        return 0;
                }
            }
            return 0;
        }

        public object Clone()
        {
            return new MyPoint { X = this.X, Y = this.Y, Z = this.Z };
        }

        public IEnumerator GetEnumerator()
        {
            return new MyEnumerator(this);
        }

        public IEnumerable GetPoints(bool b)
        {
            return new MyEnumerable(this);
        }

        class MyEnumerable : IEnumerable
        {
            MyPoint p;

            public MyEnumerable(MyPoint p)
            {
                this.p = p;
            }

            public IEnumerator GetEnumerator()
            {
                return new MyPoint.MyEnumerator(p);
            }
        }

        class MyEnumerator : IEnumerator
        {
            MyPoint[] arr;
            int len;
            int i;

            public MyEnumerator(MyPoint x)
            {
                arr = x.arr;
                len = x.arr.Length;
                i = 0;
            }

            public bool MoveNext()
            {
                return i != len ? true : false;
            }

            public object Current
            {
                get
                {
                    return arr[i++];
                }
            }

            public void Reset()
            {
                i = 0;
            }
        }

        public void FillArray(int n)
        {
            arr = new MyPoint[n];
            for (int i = 0; i < n; i++)
                arr[i] = new MyPoint { X = i, Y = i + 1, Z = i + 2 };
        }
        
        public override string ToString()
        {
            return String.Format("First field = {0}\nSecond field = {1}\nThird field = {2}\n", x, y, z);
        }

        public override bool Equals(object obj)
        {
            MyPoint p = obj as MyPoint;
            if (p != null)
            {
                if (this.x == p.x && this.y == p.y && this.Z == p.Z)
                    return true;
            }

            return false;
        }

        public override int GetHashCode()
        {
            return this.ToString().GetHashCode();
        }

        public static MyPoint operator + (MyPoint p1, MyPoint p2)
        {
            //null reference
            return new MyPoint { X = p1.X + p2.X, Y = p1.Y + p2.Y, Z = p1.Z + p2.Z };
        }

        public static MyPoint operator + (MyPoint p1, int i)
        {
            return new MyPoint { X = p1.X + i, Y = p1.Y + i, Z = p1.Z + i };
        }

        public static MyPoint operator ++ (MyPoint p1)
        {
            return new MyPoint { X = p1.X + 1, Y = p1.Y + 1, Z = p1.Z + 1 };
        }

        public static bool operator == (MyPoint p1, MyPoint p2)
        {
            if (p1 == null || p2 == null)
                return false;
            return p1.Equals(p2);
        }

        public static bool operator != (MyPoint p1, MyPoint p2)
        {
            if (p1 == null || p2 == null)
                return false;
            return !(p1.Equals(p2));
        }
    }

    class PointComparer : IComparer
        {
            public int Compare (object o1, object o2)
            {
                MyPoint p1 = o1 as MyPoint;
                MyPoint p2 = o2 as MyPoint;
                if (p1 != null && p2 != null)
                {
                    return p1.CompareTo(p2);
                }
                return 0;
            }
        }

}