Starting Out with Alice: A Visual Introduction to Programming (2e)

Preface xiii
Chapter 1 Introduction to Alice and Objects 1
1.1 What Is a Computer Program? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2 Algorithms and Programming Languages . . . . . . . . . . . . . . . . . . . . . . .2
1.3 Learning to Program with Alice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
TUTORIAL 1-1: Opening and playing an Alice world . . . . . . . . . . . . . . . . . . . . . .6
1.4 Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
1.5 Classes and the Alice Galleries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
TUTORIAL 1-2: Creating a world and adding objects . . . . . . . . . . . . . . . . . . . . .19
1.6 3D Objects and the Camera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
TUTORIAL 1-3: Moving the camera in 3D space . . . . . . . . . . . . . . . . . . . . . . . .34
TUTORIAL 1-4: Manipulating objects in 3D space . . . . . . . . . . . . . . . . . . . . . . .40
TUTORIAL 1-5: Manipulating subpart objects . . . . . . . . . . . . . . . . . . . . . . . . . .43
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Chapter 2 Programming in Alice 57
2.1 Writing Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
TUTORIAL 2-1: Adding instructions to an Alice world . . . . . . . . . . . . . . . . . . . .62
TUTORIAL 2-2: Exploring additional primitive methods . . . . . . . . . . . . . . . . . .67
2.2 Naming Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
2.3 Designing a Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
TUTORIAL 2-3: Using the program design cycle . . . . . . . . . . . . . . . . . . . . . . . . .82
2.4 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
TUTORIAL 2-4: Inserting comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
2.5 Tips for Setting Up an Initial Scene . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
2.6 Executing Instructions Simultaneously . . . . . . . . . . . . . . . . . . . . . . . . .97
TUTORIAL 2-5: Creating simultaneously executed instructions . . . . . . . . . . . . .98
2.7 Exporting Your Code for Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . .104
2.8 Exporting an Alice World to Video . . . . . . . . . . . . . . . . . . . . . . . . . . .105
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106

Chapter 3 Variables, Functions, Math, and Strings 113
3.1 Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
TUTORIAL 3-1: Creating and using a variable . . . . . . . . . . . . . . . . . . . . . . . . .116
TUTORIAL 3-2: Creating a set instruction for a variable . . . . . . . . . . . . . . . . .118
3.2 Using Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
TUTORIAL 3-3: Calling an ask user function . . . . . . . . . . . . . . . . . . . . . . . . .122
TUTORIAL 3-4: Using a proximity function . . . . . . . . . . . . . . . . . . . . . . . . . . .127
3.3 Creating Math Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130
TUTORIAL 3-5: Using math to avoid collisions . . . . . . . . . . . . . . . . . . . . . . . .132
3.4 Working with Strings and Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .138
TUTORIAL 3-6: Converting a Number variable to a string . . . . . . . . . . . . . . . .141
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .144

Chapter 4 Decision and Repetition Structures 151
4.1 Boolean Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151
4.2 The If/Else Decision Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153
TUTORIAL 4-1: Creating an If/Else instruction . . . . . . . . . . . . . . . . . . . . . . .156
4.3 Relational Comparisons and Logical Operators . . . . . . . . . . . . . . . . . .163
TUTORIAL 4-2: Using a relational operator . . . . . . . . . . . . . . . . . . . . . . . . . . .165
TUTORIAL 4-3: Testing an object’s color property . . . . . . . . . . . . . . . . . . . . . .169
4.4 The Loop Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174
TUTORIAL 4-4: Using the Loop instruction . . . . . . . . . . . . . . . . . . . . . . . . . . .175
4.5 The While Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .180
TUTORIAL 4-5: Using a While instruction to make an object vanish . . . . . . . .182
TUTORIAL 4-6: Using the While instruction to move an object . . . . . . . . . . . .186
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189

Chapter 5 Methods, Functions, and More about Variables 195
5.1 Writing Custom Class-Level Methods . . . . . . . . . . . . . . . . . . . . . . . . .195
TUTORIAL 5-1: Creating a class-level method . . . . . . . . . . . . . . . . . . . . . . . . .196
5.2 Saving an Object to a New Class . . . . . . . . . . . . . . . . . . . . . . . . . . . .199
TUTORIAL 5-2: Saving an object to a class . . . . . . . . . . . . . . . . . . . . . . . . . . . .200
5.3 Stepwise Refinement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .203
TUTORIAL 5-3: Completing the WorkOut world . . . . . . . . . . . . . . . . . . . . . . .207
5.4 Passing Arguments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .209
TUTORIAL 5-4: Passing arguments to a method . . . . . . . . . . . . . . . . . . . . . . . .211
5.5 Using Class-Level Variables as Properties . . . . . . . . . . . . . . . . . . . . . . .215
TUTORIAL 5-5: Adding a property to an object . . . . . . . . . . . . . . . . . . . . . . . .217
5.6 Writing Class-Level Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .220
TUTORIAL 5-6: Writing a class-level function . . . . . . . . . . . . . . . . . . . . . . . . .221
5.7 World-Level Methods and Variables . . . . . . . . . . . . . . . . . . . . . . . . . .226
5.8 Using Clipboards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .229
5.9 Tips for Visual Effects and Animation . . . . . . . . . . . . . . . . . . . . . . . . .230
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .241

Chapter 6 Events 249
6.1 Responding to Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .249
6.2 Handling Key Press and Mouse Events . . . . . . . . . . . . . . . . . . . . . . . .253
TUTORIAL 6-1: Handling key press events . . . . . . . . . . . . . . . . . . . . . . . . . . . .254
TUTORIAL 6-2: Handling the while a key is pressed event . . . . . . . . . . .258
TUTORIAL 6-3: Handling a mouse click event . . . . . . . . . . . . . . . . . . . . . . . . .261
6.3 Using Events in Simulations and Games . . . . . . . . . . . . . . . . . . . . . . .264
6.4 Tips for Games and Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . .268
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .275

Chapter 7 Lists and Arrays 281
7.1 Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .281
TUTORIAL 7-1: Creating a list and using the For all in order and For all together instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .285
TUTORIAL 7-2: More complex list processing . . . . . . . . . . . . . . . . . . . . . . . . .291
TUTORIAL 7-3: Using the Let the mouse move <objects> event . . . . . . . .305
7.2 Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .308
TUTORIAL 7-4: Creating an array and a loop that steps through it . . . . . . . . .311
TUTORIAL 7-5: Randomly selecting an array element . . . . . . . . . . . . . . . . . . .317
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .319

Chapter 8 Recursion 323
8.1 Introduction to Recursion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .323
TUTORIAL 8-1: Creating a recursive method . . . . . . . . . . . . . . . . . . . . . . . . . .327
8.2 Problem Solving with Recursion . . . . . . . . . . . . . . . . . . . . . . . . . . . . .330
TUTORIAL 8-2: Recursive problem solving in animation . . . . . . . . . . . . . . . . .331
TUTORIAL 8-3: Writing a recursive mathematical function . . . . . . . . . . . . . . .336
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .338
Appendix A Installing Alice 343
Appendix B Answers to Checkpoints 347
Index 355

• Online VideoNotes - An extensive series of online VideoNotes have been developed to accompany this text. Created by author Tony Gaddis, VideoNotes provide extra examples and demonstrate how to solve problems. Throughout the book, VideoNote icons alert the student to videos that explain many of the books hands-on tutorials. Additionally, one programming exercise at the end of each chapter now has an accompanying VideoNote explaining how to develop the problem's solution. The VideoNotes are available to instructors and students through a password-protected companion website. An access code to the companion website is included with the purchase of a new copy of the textbook.
• Updated for Alice 2.2 - This book has been updated for compatibility with Alice 2.2
• Exporting an Alice World to Video - Chapter 2 discusses the process of exporting an Alice world to video.
• Expanded Coverage of Decision Structures - Chapter 4, Decision and Repetition Structures, has a new section on testing the value of an object's property with an If/Else instruction, a new tutorial on testing an object's color property.
• Expanded Coverage of Repetition Structures - Chapter 4, Decision and Repetition Structures, has a new tutorial on using a While instruction to repeatedly manipulate an object's opacity property.
• Additional Programming Problems - Additional programming problems have been added to Chapters 1, 2, 4, and 5. Many of these new problems are designed to focus on a small set of topics from their chapter, and can be completed in a short period of time.
  

• Using Alice, program structures are displayed as tangible objects, and students use a drag-and-drop interface to move tiles—people, animals, fantasy creatures, and vehicles—into an editor. Students can “flip a switch” to see the Java programming structures hidden behind the scenes.
• The Gaddis style, supported by Alice’s simplistic learning methodology, eases students into programming language and helps them recognize and avoid errors as they develop their skills.
• The full-color design complements the virtual Alice world, helping students to relate the text’s step-by-step explanations to the on-screen environment through screen shots.
• Concept boxes throughout the chapter focus students’ attention on key topics.
• Notes explain interesting or often misunderstood points relevant to the topic at hand.
• Tutorials guide students through several exercises per chapter, ensuring student understanding of the material.
• Tips advise students on the best techniques for particular actions.
• Warnings alert students to common missteps or problems they may encounter.
• Checkpoints at key locations in each chapter check students’ understanding of important lessons.
• This text can be used in a variety of courses, from a standalone introductory course using Alice, as the initial teaching tool in a CS1 course, or for programming in a fluency course.
• VideoNotes are step-by-step video tutorials specifically designed to enhance the programming concepts presented in Gaddis, Starting out with Alice: A Visual Introduction To Programming, 2e. Students can view the entire problem-solving process outside of the classroom–when they need help the most. VideoNotes are available with the purchase of a new copy of select titles. Go to www.pearsonhighered.com/videonotes for a brief VideoNotes demo.
  

• VideoNotes Companion Website for Starting Out with Alice: A Visual Introduction to Programming
  http://www.pearsonhighered.com/gaddis/