Pr10ex3

Program.cs
______________
using System;

namespace test
{
    class Program
    {
        static void Main ()
        {
            Rectangle firstRectangle = new Rectangle (-1,2);
            firstRectangle.Show ();
            Console.WriteLine ();

            firstRectangle.A = 4;
            firstRectangle.B = 4;

            firstRectangle.Show ();
            if (firstRectangle)
                Console.WriteLine ("Is Square");

            int x = firstRectangle.GetPerimetr();
            int y = firstRectangle.GetSquare();
            Console.WriteLine ("Perimetr = {0}; Square = {1} ",
                x, y);

            Console.WriteLine ();

            firstRectangle [0] = 9;
            firstRectangle [1] = 9;
            firstRectangle [2] = 0;
            firstRectangle++;
            firstRectangle.Show ();

            firstRectangle *= 4;
            firstRectangle.Show ();

            int s = firstRectangle.isSquare;
        }
    }
}

____________________
Rectangle.cs
____________________
using System;

namespace test
{
    public class Rectangle
    {
        private int a;
        private int b;

        //конструкторы
        public Rectangle ()
        {
        }

        public Rectangle (int a, int b)
        {
            if (a > 0 && b > 0)
            {
                this.a = a;
                this.b = b;
            }
            else
                Console.WriteLine ("Incorrect a or b");
        }

        //методы: вывод на экран, подсчет периметра и площади
        public void Show()
        {
            Console.WriteLine ("Rectangle with side a = {0} and side b = {1}", a, b);
        }

        public int GetPerimetr()
        {
            return 2*(a+b);
        }

        public int GetSquare()
        {
            return a*b;
        }

        //свойства
        public int A
        {
            get
            {
                return a;
            }
            set
            {
                if (value > 0)
                    a = value;
                else
                {
                    a = 0;
                    Console.WriteLine ("Incorrect a");
                }
            }
        }

        public int B
        {
            get
            {
                return b;
            }
            set
            {
                if (value > 0)
                    b = value;
                else
                {
                    b = 0;
                    Console.WriteLine ("Incorret b");
                }
            }
        }

        public int isSquare
        {
            get
            {
                if (a == b)
                {
                    Console.WriteLine("Rectangle is Square");
                    return 0;
                }
                else return 0;
            }
        }

        //индексатор
        public int this [int i]
        {
            get
            {
                if (i == 0)
                    return a;
                else if (i == 1)
                    return b;
                else
                {
                    Console.WriteLine ("Error: index");
                    return 0;
                }
            }
            set
            {
                if (i == 0 && value > 0)
                    a = value;
                else if (i == 1 && value > 0)
                    b = value;
                else
                    Console.WriteLine ("Error: index or value");
            }
        }

        //перегрузка операций
        public static Rectangle operator ++ (Rectangle x)
        {
            x.A += 1;
            x.B += 1;
            return x;
        }

        public static Rectangle operator -- (Rectangle x)
        {
            x.A -= 1;
            x.B -= 1;
            return x;
        }

        public static Rectangle operator * (Rectangle x, int y)
        {
            x.A *= y;
            x.B *= y;
            return x;
        }

        public static bool operator true (Rectangle x)
        {
            if (x.a == x.b)
                return true;
            else
                return false;
        }

        public static bool operator false (Rectangle x)
        {
            if (x.a == x.b)
                return true;
            else
                return false;
        }
    }
}