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About the Presentations

About the Presentations. The presentations cover the objectives found in the opening of each chapter. All chapter objectives are listed in the beginning of each presentation. You may customize the presentations to fit your class needs.

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About the Presentations

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  1. About the Presentations • The presentations cover the objectives found in the opening of each chapter. • All chapter objectives are listed in the beginning of each presentation. • You may customize the presentations to fit your class needs. • Some figures from the chapters are included. A complete set of images from the book can be found on the Instructor Resources disc.

  2. Invitation to Computer Science 5thEdition Chapter 1 An Introduction to Computer Science 2

  3. Objectives In this chapter, you will learn about: • The definition of computer science • Algorithms • A brief history of computing • Organization of the text Invitation to Computer Science, 5th Edition

  4. Introduction • Misconceptions • Computer science is: • The study of computers • The study of how to write computer programs • The study of the uses and applications of computers and software Invitation to Computer Science, 5th Edition

  5. The Definition of Computer Science • Computer science isthe study of algorithms, including: • Their formal and mathematical properties • Their hardware realizations • Their linguistic realizations • Their applications Invitation to Computer Science, 5th Edition

  6. The Definition of Computer Science (continued) • Algorithm • Step-by-step method for accomplishing some task • Operations used to construct algorithms • Sequential operations • Conditional operations • Iterative operations Invitation to Computer Science, 5th Edition

  7. Figure 1.1 Programming Your DVR. An Example of an Algorithm Invitation to Computer Science, 5th Edition

  8. Figure 1.2 Algorithm for Adding Two m-digit Numbers Invitation to Computer Science, 5th Edition

  9. The Definition of Computer Science (continued) • Why are formal algorithms so important in computer science? • If we can specify an algorithm to solve a problem, then we can automate its solution • Computing agent • Machine, robot, person, or thing carrying out the steps of the algorithm Invitation to Computer Science, 5th Edition

  10. Algorithms • Algorithm • Well-ordered collection of unambiguous and effectively computable operations that, when executed, produces a result and halts in a finite amount of time • Ambiguous statements • Go back and do it again (Do what again?) • Start over (From where?) Invitation to Computer Science, 5th Edition

  11. Algorithms (continued) • Unambiguousoperation • Can be understood and carried out directly by the computing agent without further simplification or explanation • Also called primitive operation • It is not enough for an operation to be understandable • It must also be doable (effectively computable)by the computing agent Invitation to Computer Science, 5th Edition

  12. Algorithms (continued) • Algorithm • Result must be produced after the execution of a finite number of operations • Infinite loop • Runs forever Invitation to Computer Science, 5th Edition

  13. Figure 1.3a A Correct Solution to the Shampooing Problem Invitation to Computer Science, 5th Edition

  14. Figure 1.3b Another Correct Solution to the Shampooing Problem Invitation to Computer Science, 5th Edition

  15. The Importance of Algorithmic Problem Solving • “Computer revolution” of the twentieth and twenty-first centuries • Has enabled us to implement algorithms that mechanize and automate the drudgery of repetitive mental tasks Invitation to Computer Science, 5th Edition

  16. A Brief History of Computing • The Early Period: Up to 1940 • John Napier invented logarithms as a way to simplify difficult mathematical computations • The first slide rule appeared around 1622 • Blaise Pascal designed and built one of the first mechanical calculators (named the Pascaline) • Gottfried Leibnitz constructed a mechanical calculator called Leibnitz’s Wheel Invitation to Computer Science, 5th Edition

  17. Figure 1.4 The Pascaline. One of the Earliest Mechanical Calculators Invitation to Computer Science, 5th Edition

  18. The Early Period: Up to 1940 • Difference Engine • Could do addition, subtraction, multiplication, and division to six significant digits • Could solve polynomial equations and other complex mathematical problems • Babbage’s Analytic Engine • Amazingly similar in design to a modern computer Invitation to Computer Science, 5th Edition

  19. The Early Period: Up to 1940 (continued) • Herman Hollerith • Designed and built programmable card-processing machines that could automatically read, tally, and sort data entered on punched cards • Founded the Computer Tabulating Recording Company • In 1924, Hollerith’s tabulating machine company changed its name to IBM Invitation to Computer Science, 5th Edition

  20. The Birth of Computers: 1940–1950 • Mark I • General-purpose, electromechanical programmable computer that used a mix of relays, magnets, and gears to process and store data • ENIAC (Electronic Numerical Integrator and Calculator) • Completed in 1946 • First fully electronic general-purpose programmable computer Invitation to Computer Science, 5th Edition

  21. The Birth of Computers: 1940–1950 (continued) • John Von Neumann • Proposed a radically different computer design based on a model called the stored program computer • Research group at the University of Pennsylvania built one of the first stored program computers, called EDVAC, in 1951 Invitation to Computer Science, 5th Edition

  22. The Modern Era: 1950 to the Present • First generation of computing • 1950 to 1957 • Second generation(1957–1965) • Era of FORTRAN and COBOL • The occupation called programmer was born Invitation to Computer Science, 5th Edition

  23. The Modern Era: 1950 to the Present (continued) • Third generation(1965 to 1975) • Era of the integrated circuit • Birth of the first minicomputer • Birth of the software industry • Fourth generation (1975 to 1985) • Saw the appearance of the first microcomputer and computer network • Electronic mail became an important application Invitation to Computer Science, 5th Edition

  24. The Modern Era: 1950 to the Present (continued) • Fifth generation (1985–?) • Massively parallel processors capable of quadrillions (1015) of computations per second • Handheld digital devices and other types of personal digital assistants (PDAs) • High-resolution graphics for imaging, animation, movie making, and virtual reality Invitation to Computer Science, 5th Edition

  25. Figure 1.8 Some of the Major Advancements in Computing Invitation to Computer Science, 5th Edition

  26. Organization of the Text Figure 1.9 Organization of the Text into a Six-Layer Hierarchy Invitation to Computer Science, 5th Edition

  27. Summary • Computer science is the study of algorithms • An algorithm is a well-ordered collection of unambiguous and effectively computable operations that, when executed, produces a result and halts in a finite amount of time • If we can specify an algorithm to solve a problem, then we can automate its solution • Computers developed from mechanical calculating devices to modern electronic marvels of miniaturization Invitation to Computer Science, 5th Edition

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