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1、Chapter 0Introduction* 2007 Pearson Addison-Wesley. All rights reserved1 2007 Pearson Addison-Wesley. All rights reservedChapter 0: Introduction 0.1 The Role of Algorithms 0.2 The Origins of Computing Machines 0.3 The Science of Algorithms 0.4 Abstraction 0.5 An Outline of Our Study 0.6 Social Reper
2、cussions2 2007 Pearson Addison-Wesley. All rights reservedTerminology Algorithm: A set of steps that defines how a task is performed Program: A representation of an algorithm Programming: The process of developing a program Software: Programs and algorithms. Hardware: Equipment3 2007 Pearson Addison
3、-Wesley. All rights reservedFigure 0.1 An algorithm for a magic trick4 2007 Pearson Addison-Wesley. All rights reservedHistory of Algorithms The study of algorithms was originally a subject in mathematics. Early examples of algorithms Long division algorithm Euclidean Algorithm Gdels Incompleteness
4、Theorem: Some problems cannot be solved by algorithms.5 2007 Pearson Addison-Wesley. All rights reservedFigure 0.2 The Euclidean algorithm6 2007 Pearson Addison-Wesley. All rights reservedOrigins of Computing Machines Early computing devices Abacus: positions of beads represent numbers Gear-based ma
5、chines (1600s-1800s) Positions of gears represent numbers Blaise Pascal, Wilhelm Leibniz, Charles Babbage7 2007 Pearson Addison-Wesley. All rights reservedFigure 0.3 An Abacus8 2007 Pearson Addison-Wesley. All rights reservedEarly Data Storage Punched cards First used in Jacquard Loom (1801) to stor
6、e patterns for weaving cloth Stored programs in Babbages Analytical Engine Popular through the 1970s Gear positions9 2007 Pearson Addison-Wesley. All rights reservedEarly Computers Based on mechanical relays 1940: Stibitz at Bell Laboratories 1944: Mark I: Howard Aiken and IBM at Harvard Based on va
7、cuum tubes 1937-1941: Atanasoff-Berry at Iowa State 1940s: Colossus: secret German code-breaker 1940s: ENIAC: Mauchly & Eckert at U. of Penn.10 2007 Pearson Addison-Wesley. All rights reservedFigure 0.4 The Mark I computer11 2007 Pearson Addison-Wesley. All rights reservedPersonal Computers First us
8、ed by hobbyists IBM introduced the PC in 1981 Accepted by business Became the standard hardware design for most desktop computers Most PCs use software from Microsoft12 2007 Pearson Addison-Wesley. All rights reservedComputer Science The science of algorithms Draws from other subjects, including Mat
9、hematics Engineering Psychology Business Administration Psychology13 2007 Pearson Addison-Wesley. All rights reservedCentral Questions of Computer Science Which problems can be solved by algorithmic processes? How can algorithm discovery be made easier? How can techniques of representing and communi
10、cating algorithms be improved? How can our knowledge of algorithms and technology be applied to provide better machines? How can characteristics of different algorithms be analyzed and compared?14 2007 Pearson Addison-Wesley. All rights reservedFigure 0.5 The central role of algorithms in computer s
11、cience15 2007 Pearson Addison-Wesley. All rights reservedAbstraction Abstraction: The distinction between the external properties of an entity and the details of the entitys internal composition Abstract tool: A “component” that can be used without concern for the components internal properties16 20
12、07 Pearson Addison-Wesley. All rights reservedOutline of Our Study Chapter 1: Data Storage Chapter 2: Data Manipulation Chapter 3: Operating Systems Chapter 4: Networks and the Internet Chapter 5: Algorithms17 2007 Pearson Addison-Wesley. All rights reservedOutline of Our Study (continued) Chapter 6
13、: Programming Languages Chapter 7: Software Engineering Chapter 8: Data Abstractions Chapter 9: Database Systems Chapter 10: Artificial Intelligence Chapter 11: Theory of Computation18 2007 Pearson Addison-Wesley. All rights reservedSocial Repercussions Advances in computer science raise new questio
14、ns. In law: Questions of rights and liabilities In government: Questions of regulation In the work place: Questions of professionalism In society: Questions of social behavior19 2007 Pearson Addison-Wesley. All rights reservedEthical Theories Consequence based: What leads to the greatest benefit? Duty based: What are my intrinsic obligations? Contract based: What contracts must I honor? Character based: Who do I want to be?20 2007 Pearson Addison-Wesley. All rights reserved
