GSM

/*Define a class that holds information about a mobile phone device: model, manufacturer, price, owner, battery characteristics (model, hours idle and hours talk) and display characteristics (size and number of colors). Define 3 separate classes (class GSM holding instances of the classes Battery and Display).*/

namespace GSM
{
    using System;
    using System.Text;
    using System.Collections.Generic;
    //model, manufacturer, price, owner
    public class GSM
    {
        private readonly string model = null; //Declare only once
        private readonly string manufacturer = null;
        private int price = 0;
        private string owner = null;
        private Battery batery;
        private Display display;

        //private Display displayCharacters = new Display();

        public string Model
        {
            get { return this.model; }
        }
        public string Manufacturer
        {
            get { return this.manufacturer; }
        }
        public int Price
        {
            get { return this.price; }
            set
            {
                if (value < 0)
                {
                    throw new ArgumentException("Invalid price : price can't be negative");
                }
                this.price = value;
            }
        } // check for price
        public string Owner
        {
            get { return this.owner; }
            set { this.owner = value; }
        }

        public GSM(string model, string manufacturer, int price, string owner)
        {
            this.model = model;
            this.manufacturer = manufacturer;
            this.price = price;
            this.owner = owner;
            this.batery = new Battery();
            this.display = new Display();
        }

        static void Main()
        {
            GSM firstGsm = new GSM("E51", "Manja", 700, "Pencho");
            firstGsm.batery.Model = "Li/Ion";
            firstGsm.batery.HoursIdle = 7;
            firstGsm.batery.HoursTalk = 7;
            firstGsm.display.Color = "16 milion";
            firstGsm.display.Size = "3 inch";
        }
    }
}