public GSM(string model, string manufacturer, decimal price,
string owner, Battery baterry, Display display)
{
this.Model = model;
this.Manufacturer = manufacturer;
this.Price = price;
this.Owner = owner;
this.BatteryCharacterisitcs = baterry;
this.DisplayCharacterisitcs = display;
this.CallHistory = new List<Call>();
}
public GSM(string model, string manufacturer, decimal price, Display display)
: this(model, manufacturer, price, null, null, display)
{
}