Book class

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

namespace OBJECTORIENTATEDCODE
{
    class Program
    {
        static void Main(string[] args)
        {
            Book potter = new Book()
            {
                author = "JK Rowling",
                title = "Harry Potter and the Philosiphers stone",
                Numpages = 223,
                Cost = 4.99
            };

            potter.display();
            potter.Discount();

        }
    }




    class Book
    {




        public string author;
        public string title;
        public int Numpages;
        public double Cost;

        public void display()
        {
            Console.WriteLine("Author " + this.author);
            Console.WriteLine("Title " + this.title);
            Console.WriteLine("Number of pages " + this.Numpages);
            Console.WriteLine("Cost £ " + this.Cost);
        }

        public void Discount()
        {
            Console.WriteLine(this.Cost * 0.9);
        }
    }
}