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[CHAPTER] 1 INTRODUCTION 11.1 Two Fundamental Ideas of Computer Science: Algorithms and Information
Processing .................................................................................................................21.1.1 Algorithms ................................................................................................21.1.2 Information Processing............................................................................4
1.1 Exercises....................................................................................................................51.2 The Structure of a Modern Computer System.......................................................6
1.2.1 Computer Hardware ................................................................................61.2.2 Computer Software..................................................................................8
1.2 Exercises..................................................................................................................101.3 A Not-So-Brief History of Computing Systems...................................................10
1.3.1 Before Electronic Digital Computers ...................................................111.3.2 The First Electronic Digital Computers (1940–1950) .........................151.3.3 The First Programming Languages (1950–1965).................................161.3.4 Integrated Circuits, Interaction, and Timesharing (1965–1975) .........181.3.5 Personal Computing and Networks (1975–1990) ................................191.3.6 Consultation, Communication, and Ubiquitous Computing
(1990–Present)........................................................................................211.4 Getting Started with Python Programming..........................................................23
1.4.1 Running Code in the Interactive Shell .................................................231.4.2 Input, Processing, and Output...............................................................251.4.3 Editing, Saving, and Running a Script ..................................................281.4.4 Behind the Scenes: How Python Works ...............................................29
1.4 Exercises..................................................................................................................301.5 Detecting and Correcting Syntax Errors...............................................................311.5 Exercises..................................................................................................................32
Suggestions for Further Reading ...........................................................................32Summary .................................................................................................................33Review Questions ...................................................................................................35Projects....................................................................................................................37
[CHAPTER] 2 SOFTWARE DEVELOPMENT, DATA TYPES, AND EXPRESSIONS 39
2.1 The Software Development Process .....................................................................402.1 Exercises..................................................................................................................432.2 Case Study: Income Tax Calculator.......................................................................43
2.2.1 Request ...................................................................................................432.2.2 Analysis ...................................................................................................442.2.3 Design.....................................................................................................442.2.4 Implementation (Coding) ......................................................................452.2.5 Testing ....................................................................................................46
Table of Contents
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2.3 Strings, Assignment, and Comments.....................................................................472.3.1 Data Types..............................................................................................472.3.2 String Literals.........................................................................................482.3.3 Escape Sequences ...................................................................................502.3.4 String Concatenation .............................................................................502.3.5 Variables and the Assignment Statement ..............................................512.3.6 Program Comments and Docstrings.....................................................52
2.3 Exercises..................................................................................................................532.4 Numeric Data Types and Character Sets ..............................................................54
2.4.1 Integers ...................................................................................................542.4.2 Floating-Point Numbers........................................................................552.4.3 Character Sets ........................................................................................55
2.4 Exercises..................................................................................................................572.5 Expressions .............................................................................................................58
2.5.1 Arithmetic Expressions ..........................................................................582.5.2 Mixed-Mode Arithmetic and Type Conversions ..................................60
2.5 Exercises..................................................................................................................632.6 Using Functions and Modules ...............................................................................63
2.6.1 Calling Functions: Arguments and Return Values................................642.6.2 The math Module .................................................................................652.6.3 The Main Module..................................................................................662.6.4 Program Format and Structure .............................................................672.6.5 Running a Script from a Terminal Command Prompt ........................68
2.6 Exercises..................................................................................................................70Summary .................................................................................................................70Review Questions ...................................................................................................72Projects....................................................................................................................73
[CHAPTER] 3 CONTROL STATEMENTS 753.1 Definite Iteration: The for Loop.........................................................................76
3.1.1 Executing a Statement a Given Number of Times ..............................763.1.2 Count-Controlled Loops .......................................................................773.1.3 Augmented Assignment .........................................................................793.1.4 Loop Errors: Off-by-One Error............................................................803.1.5 Traversing the Contents of a Data Sequence........................................803.1.6 Specifying the Steps in the Range .........................................................813.1.7 Loops That Count Down......................................................................82
3.1 Exercises..................................................................................................................833.2 Formatting Text for Output ...................................................................................833.2 Exercises..................................................................................................................863.3 Case Study: An Investment Report........................................................................87
3.3.1 Request ...................................................................................................873.3.2 Analysis ...................................................................................................873.3.3 Design.....................................................................................................883.3.4 Implementation (Coding) ......................................................................883.3.5 Testing ....................................................................................................90
3.4 Selection: if and if-else Statements ...............................................................913.4.1 The Boolean Type, Comparisons, and Boolean Expressions ...............913.4.2 if-else Statements .............................................................................92
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3.4.3 One-Way Selection Statements.............................................................943.4.4 Multi-way if Statements ......................................................................953.4.5 Logical Operators and Compound Boolean Expressions.....................973.4.6 Short-Circuit Evaluation .......................................................................993.4.7 Testing Selection Statements ...............................................................100
3.4 Exercises................................................................................................................1013.5 Conditional Iteration: The while Loop ............................................................102
3.5.1 The Structure and Behavior of a while Loop ..................................1023.5.2 Count Control with a while Loop....................................................1043.5.3 The while True Loop and the break Statement ..........................1053.5.4 Random Numbers................................................................................1073.5.5 Loop Logic, Errors, and Testing .........................................................109
3.5 Exercises................................................................................................................1093.6 Case Study: Approximating Square Roots...........................................................110
3.6.1 Request .................................................................................................1103.6.2 Analysis .................................................................................................1103.6.3 Design...................................................................................................1103.6.4 Implementation (Coding) ....................................................................1123.6.5 Testing ..................................................................................................113Summary ...............................................................................................................113Review Questions .................................................................................................116Projects..................................................................................................................118
[CHAPTER] 4 STRINGS AND TEXT FILES 1214.1 Accessing Characters and Substrings in Strings..................................................122
4.1.1 The Structure of Strings......................................................................1224.1.2 The Subscript Operator.......................................................................1234.1.3 Slicing for Substrings ...........................................................................1244.1.4 Testing for a Substring with the in Operator ....................................125
4.1 Exercises................................................................................................................1264.2 Data Encryption ...................................................................................................1264.2 Exercises................................................................................................................1294.3 Strings and Number Systems...............................................................................129
4.3.1 The Positional System for Representing Numbers............................1304.3.2 Converting Binary to Decimal ............................................................1314.3.3 Converting Decimal to Binary ............................................................1324.3.4 Conversion Shortcuts...........................................................................1334.3.5 Octal and Hexadecimal Numbers .......................................................134
4.3 Exercises................................................................................................................1364.4 String Methods .....................................................................................................1364.4 Exercises................................................................................................................1404.5 Text Files ...............................................................................................................141
4.5.1 Text Files and Their Format................................................................1414.5.2 Writing Text to a File ..........................................................................1424.5.3 Writing Numbers to a File ..................................................................1424.5.4 Reading Text from a File .....................................................................1434.5.5 Reading Numbers from a File .............................................................1454.5.6 Accessing and Manipulating Files and Directories on Disk...............146
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4.5 Exercises................................................................................................................1484.6 Case Study: Text Analysis.....................................................................................148
4.6.1 Request .................................................................................................1494.6.2 Analysis .................................................................................................1494.6.3 Design...................................................................................................1504.6.4 Implementation (Coding) ....................................................................1514.6.5 Testing ..................................................................................................152Summary ...............................................................................................................153Review Questions .................................................................................................154Projects..................................................................................................................156
[CHAPTER] 5 LISTS AND DICTIONARIES 1595.1 Lists .......................................................................................................................160
5.1.1 List Literals and Basic Operators ........................................................1605.1.2 Replacing an Element in a List ...........................................................1635.1.3 List Methods for Inserting and Removing Elements .........................1655.1.4 Searching a List....................................................................................1675.1.5 Sorting a List........................................................................................1685.1.6 Mutator Methods and the Value None ...............................................1685.1.7 Aliasing and Side Effects......................................................................1695.1.8 Equality: Object Identity and Structural Equivalence........................1715.1.9 Example: Using a List to Find the Median of a Set of Numbers ......1725.1.10 Tuples ...................................................................................................173
5.1 Exercises................................................................................................................1745.2 Defining Simple Functions ..................................................................................175
5.2.1 The Syntax of Simple Function Definitions .......................................1755.2.2 Parameters and Arguments..................................................................1765.2.3 The return Statement.......................................................................1775.2.4 Boolean Functions................................................................................1775.2.5 Defining a main Function...................................................................178
5.2 Exercises................................................................................................................1795.3 Case Study: Generating Sentences ......................................................................179
5.3.1 Request .................................................................................................1795.3.2 Analysis .................................................................................................1795.3.3 Design...................................................................................................1805.3.4 Implementation (Coding) ....................................................................1825.3.5 Testing ..................................................................................................183
5.4 Dictionaries...........................................................................................................1835.4.1 Dictionary Literals ...............................................................................1835.4.2 Adding Keys and Replacing Values .....................................................1845.4.3 Accessing Values...................................................................................1855.4.4 Removing Keys ....................................................................................1865.4.5 Traversing a Dictionary .......................................................................1865.4.6 Example: The Hexadecimal System Revisited....................................1885.4.7 Example: Finding the Mode of a List of Values .................................189
5.4 Exercises................................................................................................................190
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5.5 Case Study: Nondirective Psychotherapy ...........................................................1915.5.1 Request .................................................................................................1915.5.2 Analysis .................................................................................................1915.5.3 Design...................................................................................................1925.5.4 Implementation (Coding) ....................................................................1935.5.5 Testing ..................................................................................................195Summary ...............................................................................................................195Review Questions .................................................................................................196Projects..................................................................................................................198
[CHAPTER] 6 DESIGN WITH FUNCTIONS 2016.1 Functions as Abstraction Mechanisms.................................................................202
6.1.1 Functions Eliminate Redundancy........................................................2026.1.2 Functions Hide Complexity ................................................................2036.1.3 Functions Support General Methods with Systematic Variations .....2046.1.4 Functions Support the Division of Labor ...........................................205
6.1 Exercises................................................................................................................2056.2 Problem Solving with Top-Down Design...........................................................206
6.2.1 The Design of the Text-Analysis Program .........................................2066.2.2 The Design of the Sentence-Generator Program..............................2076.2.3 The Design of the Doctor Program ...................................................209
6.2 Exercises................................................................................................................2106.3 Design with Recursive Functions ........................................................................211
6.3.1 Defining a Recursive Function............................................................2116.3.2 Tracing a Recursive Function ..............................................................2136.3.3 Using Recursive Definitions to Construct Recursive Functions .......2146.3.4 Recursion in Sentence Structure .........................................................2146.3.5 Infinite Recursion.................................................................................2156.3.6 The Costs and Benefits of Recursion..................................................216
6.3 Exercises................................................................................................................2186.4 Case Study: Gathering Information from a File System ....................................219
6.4.1 Request .................................................................................................2196.4.2 Analysis .................................................................................................2206.4.3 Design...................................................................................................2226.4.4 Implementation (Coding) ....................................................................224
6.5 Managing a Program’s Namespace ......................................................................2276.5.1 Module Variables, Parameters, and Temporary Variables ..................2276.5.2 Scope.....................................................................................................2286.5.3 Lifetime ................................................................................................2296.5.4 Default (Keyword) Arguments ............................................................230
6.5 Exercises................................................................................................................2326.6 Higher-Order Functions (Advanced Topic) ........................................................233
6.6.1 Functions as First-Class Data Objects ................................................2336.6.2 Mapping................................................................................................2346.6.3 Filtering ................................................................................................2366.6.4 Reducing...............................................................................................2376.6.5 Using lambda to Create Anonymous Functions...............................2376.6.6 Creating Jump Tables ..........................................................................238
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6.6 Exercises................................................................................................................239Summary ...............................................................................................................240Review Questions .................................................................................................242Projects..................................................................................................................244
[CHAPTER] 7 SIMPLE GRAPHICS AND IMAGE PROCESSING 2477.1 Simple Graphics ...................................................................................................248
7.1.1 Overview of Turtle Graphics ...............................................................2487.1.2 Turtle Operations.................................................................................2497.1.3 Object Instantiation and the turtle Module ...................................2527.1.4 Drawing Two-Dimensional Shapes .....................................................2547.1.5 Taking a Random Walk........................................................................2557.1.6 Colors and the RGB System................................................................2567.1.7 Example: Drawing with Random Colors ............................................2577.1.8 Examining an Object’s Attributes ........................................................2597.1.9 Manipulating a Turtle’s Screen ............................................................2597.1.10 Setting up a cfg File and Running IDLE..........................................260
7.1 Exercises................................................................................................................2617.2 Case Study: Recursive Patterns in Fractals..........................................................262
7.2.1 Request .................................................................................................2637.2.2 Analysis .................................................................................................2637.2.3 Design...................................................................................................2647.2.4 Implementation (Coding) ....................................................................266
7.3 Image Processing .................................................................................................2677.3.1 Analog and Digital Information .........................................................2677.3.2 Sampling and Digitizing Images .........................................................2687.3.3 Image File Formats ..............................................................................2687.3.4 Image-Manipulation Operations .........................................................2697.3.5 The Properties of Images ....................................................................2707.3.6 The images Module ..........................................................................2707.3.7 A Loop Pattern for Traversing a Grid ................................................2747.3.8 A Word on Tuples................................................................................2757.3.9 Converting an Image to Black and White ..........................................2767.3.10 Converting an Image to Grayscale......................................................2787.3.11 Copying an Image ................................................................................2797.3.12 Blurring an Image ................................................................................2807.3.13 Edge Detection ....................................................................................2817.3.14 Reducing the Image Size .....................................................................282
7.3 Exercises................................................................................................................284Summary ...............................................................................................................285Review Questions .................................................................................................286Projects..................................................................................................................288
[CHAPTER] 8 DESIGN WITH CLASSES 2938.1 Getting Inside Objects and Classes .....................................................................294
8.1.1 A First Example: The Student Class................................................2958.1.2 Docstrings ............................................................................................2988.1.3 Method Definitions..............................................................................298
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8.1.4 The __init__ Method and Instance Variables................................2998.1.5 The __str__ Method........................................................................3008.1.6 Accessors and Mutators .......................................................................3008.1.7 The Lifetime of Objects ......................................................................3018.1.8 Rules of Thumb for Defining a Simple Class.....................................302
8.1 Exercises................................................................................................................3038.2 Case Study: Playing the Game of Craps .............................................................303
8.2.1 Request .................................................................................................3038.2.2 Analysis .................................................................................................3038.2.3 Design...................................................................................................3048.2.4 Implementation (Coding) ....................................................................306
8.3 Data-Modeling Examples.....................................................................................3098.3.1 Rational Numbers ................................................................................3098.3.2 Rational Number Arithmetic and Operator Overloading..................3118.3.3 Comparison Methods...........................................................................3128.3.4 Equality and the __eq__ Method ......................................................3148.3.5 Savings Accounts and Class Variables .................................................3158.3.6 Putting the Accounts into a Bank........................................................3178.3.7 Using pickle for Permanent Storage of Objects.............................3198.3.8 Input of Objects and the try-except Statement............................3208.3.9 Playing Cards .......................................................................................321
8.3 Exercises................................................................................................................3258.4 Case Study: An ATM............................................................................................325
8.4.1 Request .................................................................................................3258.4.2 Analysis .................................................................................................3258.4.3 Design...................................................................................................3278.4.4 Implementation (Coding) ....................................................................329
8.5 Structuring Classes with Inheritance and Polymorphism...................................3318.5.1 Inheritance Hierarchies and Modeling ...............................................3328.5.2 Example: A Restricted Savings Account..............................................3338.5.3 Example: The Dealer and a Player in the Game of Blackjack ...........3358.5.4 Polymorphic Methods..........................................................................3408.5.5 Abstract Classes ...................................................................................3408.5.6 The Costs and Benefits of Object-Oriented Programming...............341
8.5 Exercises................................................................................................................343Summary ...............................................................................................................343Review Questions .................................................................................................345Projects..................................................................................................................346
[CHAPTER] 9 GRAPHICAL USER INTERFACES 3499.1 The Behavior of Terminal-Based Programs and GUI-Based Programs............350
9.1.1 The Terminal-Based Version...............................................................3509.1.2 The GUI-Based Version......................................................................3519.1.3 Event-Driven Programming................................................................353
9.1 Exercises................................................................................................................3559.2 Coding Simple GUI-Based Programs .................................................................355
9.2.1 Windows and Labels ............................................................................3569.2.2 Displaying Images ................................................................................3579.2.3 Command Buttons and Responding to Events...................................3589.2.4 Viewing the Images of Playing Cards .................................................360
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9.2.5 Entry Fields for the Input and Output of Text ...................................3639.2.6 Using Pop-up Dialog Boxes ................................................................365
9.2 Exercises................................................................................................................3669.3 Case Study: A GUI-Based ATM..........................................................................367
9.3.1 Request .................................................................................................3679.3.2 Analysis .................................................................................................3679.3.3 Design...................................................................................................3689.3.4 Implementation (Coding) ....................................................................369
9.4 Other Useful GUI Resources ..............................................................................3729.4.1 Colors ...................................................................................................3739.4.2 Text Attributes......................................................................................3739.4.3 Sizing and Justifying an Entry .............................................................3749.4.4 Sizing the Main Window.....................................................................3759.4.5 Grid Attributes .....................................................................................3769.4.6 Using Nested Frames to Organize Components................................3809.4.7 Multi-Line Text Widgets .....................................................................3819.4.8 Scrolling List Boxes .............................................................................3849.4.9 Mouse Events .......................................................................................3879.4.10 Keyboard Events ..................................................................................388
9.4 Exercises................................................................................................................389Summary ...............................................................................................................390Review Questions .................................................................................................391Projects..................................................................................................................392
[CHAPTER] 10 MULTITHREADING, NETWORKS, AND CLIENT/SERVERPROGRAMMING 395
10.1 Threads and Processes .........................................................................................39610.1.1 Threads.................................................................................................39710.1.2 Sleeping Threads..................................................................................40010.1.3 Producer, Consumer, and Synchronization ........................................402
10.1 Exercises................................................................................................................40910.2 Networks, Clients, and Servers............................................................................409
10.2.1 IP Addresses .........................................................................................40910.2.2 Ports, Servers, and Clients...................................................................41110.2.3 Sockets and a Day/Time Client Script................................................41210.2.4 A Day/Time Server Script ...................................................................41410.2.5 A Two-Way Chat Script.......................................................................41610.2.6 Handling Multiple Clients Concurrently ...........................................41810.2.7 Setting Up Conversations for Others .................................................420
10.2 Exercises................................................................................................................42210.3 Case Study: A Multi-Client Chat Room .............................................................423
10.3.1 Request ................................................................................................42310.3.2 Analysis ................................................................................................42310.3.3 Design...................................................................................................42410.3.4 Implementation (Coding) ....................................................................425Summary ...............................................................................................................427Review Questions .................................................................................................428Projects..................................................................................................................430
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[ONLINE CHAPTER] 11 SEARCHING, SORTING, AND COMPLEXITY ANALYSIS (Available on the publisher’s Web site at www.cengagebrain.com.)
11.1 Measuring the Efficiency of Algorithms11.1.1 Measuring the Run Time of an Algorithm 11.1.2 Counting Instructions11.1.3 Measuring the Memory Used by an Algorithm
11.1 Exercises11.2 Complexity Analysis
11.2.1 Orders of Complexity11.2.2 Big-O Notation11.2.3 The Role of the Constant of Proportionality
11.2 Exercises11.3 Search Algorithms
11.3.1 Search for a Minimum 11.3.2 Linear Search of a List 11.3.3 Best-Case, Worst-Case, and Average-Case Performance11.3.4 Binary Search of a List11.3.5 Comparing Data Items
11.3 Exercises11.4 Sort Algorithms
11.4.1 Selection Sort11.4.2 Bubble Sort11.4.3 Insertion Sort11.4.4 Best-Case, Worst-Case, and Average-Case Performance Revisited
11.4 Exercises11.5 An Exponential Algorithm: Recursive Fibonacci11.6 Converting Fibonacci to a Linear Algorithm11.7 Case Study: An Algorithm Profiler
11.7.1 Request11.7.2 Analysis11.7.3 Design11.7.4 Implementation (Coding)SummaryReview QuestionsProjects
[APPENDIX] A PYTHON RESOURCES 433A.1 Installing Python on Your Computer ..................................................................434A.2 Using the Terminal Command Prompt, IDLE, and Other IDEs......................434
[APPENDIX] B INSTALLING THE images LIBRARY 437
[APPENDIX] C API FOR IMAGE PROCESSING 439
[APPENDIX] D TRANSITION FROM PYTHON TO JAVA AND C++ 441
GLOSSARY 443
INDEX 455
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