using System;

public class Program

{

    public class Product

    {

        public string Code { get;set;}

        public string Name { get;set;}

        public string Description { get;set;}

        public int Price { get;set;}

        public Product(string Code, string Name, string Description, int Price)

        {

            if(String.IsNullOrWhiteSpace(Code))

                throw new ArgumentNullException($"{nameof(this.Code)} cannot be empty");

            else

                this.Code =Code;

            if(String.IsNullOrWhiteSpace(Name))

                throw new ArgumentNullException($"{nameof(this.Name)} cannot be empty");

            else

                this.Name= Name;

            if(String.IsNullOrWhiteSpace(Description))

                throw new ArgumentNullException($"{nameof(this.Description)} cannot be empty");

            else

                this.Description = Description;

            if(Price <=0 )

                throw new ArgumentNullException($"{nameof(this.Price)} should be greater than 0");

            else

                this.Price= Price;

        }

        public void DisplayValues()

        {

            Console.WriteLine($"{nameof(this.Code)} - {this.Code}");

            Console.WriteLine($"{nameof(this.Name)} - {this.Name}");    

            Console.WriteLine($"{nameof(this.Description)} - {this.Description}");

            Console.WriteLine($"{nameof(this.Price)} - {this.Price}");

        }

    }

    public static void Main()

    {

        try

        {

            Console.WriteLine("With null value");

            Product prod1 = new Product(null, null,null,2);

            prod1.DisplayValues();

        }

        catch(Exception e)

        {

            Console.WriteLine(e.Message);

        }

        Console.WriteLine("\nWithout null values");

        Product prod2 = new Product("640", "Nokia 640 XL","Nokia 640 XL LTE",15000);

        prod2.DisplayValues();

    }

}