/// <summary>
/// This is the true power of interfaces. This method has a "arguement type" or "parameter type"
/// if IPhone. This means that ANY phone that implements the IPhone interface can be sent to this
/// method. The same thing will happen for all phones, and this method does not care what kind of
/// specific phone it is. Nor does it care how it does the things that it is doing.
/// </summary>
/// <param name="phone"></param>
static private void DoPhoneStuff(IPhone phone)
{
phone.Dial();
phone.PlayGame();
phone.Ring();
Console.WriteLine();
}
public void CallNumber(string phoneNumber)
{
_phone.Dial(phoneNumber);
}