public GSM(string model, string manufacturer, double price, string owner, Battery batteryType, Display displayType)
: this(model, manufacturer, price, owner,batteryType)
{
this.displayType = displayType;
}
public GSM(string model, string manufacturer, double price, string owner, Battery batteryType)
: this(model, manufacturer, price,owner)
{
this.batteryType = batteryType;
}
