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