Indexing, The Basic Idea
	v Motivation:  When there is a large number of similar things that must be referenced and manipulated, it can be inconvenient to think up a unique name for each, and to refer to them by the name ; For example:  Each of the Seven Dwarfs    has a name, but who can remember them?    Also, it is difficult to refer to them in a loop    since there is no way to enumerate them v Indexing names the items by associating a base name and a number -- the index -- with each one v Computer notation:  Dwarf(5) Û Happy