Constructors in Hierarchies
	• The initialization list causes the base class constructor to be invoked with the correct arguments! • The order of the arguments for the base class is very important. They must be listed in the same order as the base class constructor expects. •  If we had not included the base class constructor in the initialization list of the derived class, then the default base class constructor would be invoked. • If no default base class constructor exists, then a compile error results.