C# Operator overloading | compile time polymorphism

Program

using System;

namespace Polymorphism

{

    class OperatorOverloading

    {

        class Product

        {

            string _ProductName;

            int _Price;

            int _Qty;

            public Product(string pname, int price, int qty)

            {

                _ProductName = pname;

                _Price = price;

                _Qty = qty;

            }

            public void displayProductDetails()

            {

                Console.WriteLine("Product Name : {0}", _ProductName);

                Console.WriteLine("Product Price : {0}", _Price);

                Console.WriteLine("Product Qty  : {0}", _Qty);

            }

            public static Product operator +(Product Pa, Product Pb)

            {

                Product Px = new Product("", 0, 0);

                Px._ProductName = Pa._ProductName + "," + Pb._ProductName;

                Px._Qty = Pa._Qty + Pb._Qty;

                Px._Price = Pa._Price + Pb._Price;

                return Px;

            }

        }

        static void Main(string[] args)

        {

            Product p1 = new Product("Keyboard", 450, 3);

            Product p2 = new Product("Mouse", 300, 5);

            Product p3;   

            p3 = p1 + p2;

            //Now p3 receives the address from px, so object referred

            //by px in operator+() method will also be referred by p3

            //because p3 didn't refer any object previously

            p1.displayProductDetails();

            p2.displayProductDetails();

            p3.displayProductDetails();

            Console.ReadKey();

        }

    }

}

Output

Product Name    : Keyboard
Product Price   : 450
Product Qty     : 3

Product Name    : Mouse
Product Price   : 300
Product Qty     : 5

Product Name    : Keyboard,Mouse
Product Price   : 750

Product Qty     : 8