Data Abstraction
and
Represenation
General Data Characterizations
General Data Characterizations
Example: Natural Numbers
Peano Axioms (1889)
Peano vs. Decimal Presentation
Aside: PeanoÕs Space-Filling Curve
PeanoÕs Space-Filling Curve
PeanoÕs Space-Filling Curve
More Peano Curve Iterations
 (demo http://library.thinkquest.org/26242/full/fm/fm25.html?tqskip1=1&tqtime=0828)
The Purpose of Abstraction in CS
 Abstract Art: Similar meaning, but not the same purpose
Abstractions in Disciplines
Abstraction Exercise
Open-List Abstraction
Information Structures vs.
Data Structures
List Abstraction
Idea of ÒStructureÓ
List Structures
Equality for Lists
The (one and only) Empty List
Lists of Various Types of Elements
Mixing types of elements
Specialized Uses of Lists
Implementing Set Abstraction
using Lists
Lists of Lists
Lists can be Nested Arbitrarily-Deeply
Length of a List
The member function
Implementing
Other Information Structures
using Lists
Association Lists
Implementing an Ordered Dictionary
Ordered Dictionary Example
Using a Dictionary
rex function assoc
Example using assoc:
Using the rex builtin 2-ary test function