PROBLEM SOLVING USING JAVA WITH DATA STRUCTURES. A Multimedia Approach. Mark Guzdial and Barbara Ericson PEARSON. College of Computing

Transcription

1 PROBLEM SOLVING WITH DATA STRUCTURES USING JAVA A Multimedia Approach Mark Guzdial and Barbara Ericson College of Computing Georgia Institute of Technology PEARSON Boston Columbus Indianapolis New York San Francisco Upper Saddle River Amsterdam Cape Town Dubai London Madrid Milan Munich Paris Montreal Toronto Delhi Mexico City Sao Paulo Sydney Hong Kong Seoul Singapore Taipei Tokyo

2 Contents Preface 13 About the Authors 19 1 INTRODUCTION TO JAVA: OBJECT-ORIENTED PROGRAMMING FOR MODELING A WORLD 23 1 Objects for Modeling a World Making Representations of a World Why Java? 33 Getting Java Set Up 33 2 Introduction to Java What's Java About? Basic (Syntax) Rules of Java 39 Declarations and "types 39 Strings 41 ObjectVariables and Primitive Variables 42 Assignment 44 Semicolons 44 Conditionals 44 Arrays 46 Iteration 47 Strings versus Arrays and Substrings Using Java to Model the World 48 Discourse Rules for Java 53 Defining tostring 53 Defining Student as Subclass of Person 54 Creating a main() Method 57 Exploring Inheritance Manipulating Pictures in Java Exploring 2.6 Exploring Sound in Java 67 Music in Java 68

3 Methods in Java: Manipulating Pictures Reviewing Java Basics 73 Assignment 73 Arrays 75 Conditionals 75 Iteration: For each, While, and For Changing the Picture Class 77 Pictures Are About Arrays and Pixels 79 A Method for Decreasing Red 79 Method with an Input Methods That Return Something: Compositing Images 84 Composing by Chromakey Creating Classes That Do Something 93 Objects as Agents: Manipulating Turtles Turtles: An Early Computational Object Drawing with Turtles 98 When Cascades Don't Work 100 Making Lots of Turtles 101 Composing Pictures with Turtles Creating Animations with Turtles and Frames 105 The Data Structure within FrameSequencer Making a Slow Moving Turtle with sleep and Exceptions 110 Arrays: A Static Data Structure for Sounds Manipulating Sampled Sounds Inserting and Deleting in an Array How Slow Does It Get? 124 INTRODUCING LINKED LISTS 127 Structuring Music Using Linked Lists JMusic and Imports Making a Simple Song Object Making a Song Something to Explore as a Linked List 135 Walking through SongNode 143 Improving insertafter 147

4 The Contents 9 Helping Others Use Our Classes 148 Computing Phrases 149 Repeating and Weaving to Make Music 151 Linked Lists versus Arrays 154 Creating a Music Tree Structuring Images Using Linked Lists Simple Arrays of Pictures Listing the Pictures, Left-to-Right 165 Generalizing Moving the Element Listing the Pictures, Layering 171 Reordering Elements in a List Reversing a List Animation Lists with Two Kinds of Elements 181 Structuring Our Multi-Element Lists TREES: HIERARCHICAL STRUCTURES FORMEDIA Trees of Images Representing Scenes with Trees OurFirstSceneGraph:AttackoftheKillerWolvies Classes in the Scene Graph Building a Scene Graph Implementing the Scene Graph 215 Implementing the Abstract Superclass for the Scene Graph: DrawableNode 217 Implementing the Leaf Nodes: PictNode and BlueScreenNode 219 Implementing the Branches: Branch, MoveBranch, VBranch, andhbranch 221 The Line between Structure and Behavior Lists and Trees for Structuring Sounds Composing with Sampled Sounds and Linked Lists: Recursive Traversals 231 Tracing a Recursive Traversal 237 Testing and Replacing 239

5 10 Contents 9.2 Using Trees to Structure Sampled Sounds 245 Implementing a Sound Tree 249 Tracing a Recursive Tree Traversal 255 Where We're Going Next Generalizing Lists and Trees Refactoring a General Linked List Node Class 264 Making Wol fattackmovi e Work Again 267 Making Sound Trees Work Again Making a New Kind of List The Uses and Characteristics of Arrays, Lists, and Trees 275 Examples of Tree Uses Binary Search Trees: Trees That Are Fast to Search 280 Traversals of Trees 287 Trees Can Do Anything Abstract Data Types: Separating the Meaning from the Implementation Introducing Stacks 293 Defining an Abstract Data Type 294 A Stack Interface 296 Multiple Implementations of a Stack 297 Uses of a Stack Introducing Queues 305 Implementing a Queue 307 Creating an Abstract Queue Class Using an ArrayList Using a Map ADT Circular Linked Lists and Graphs: Lists and Trees That Loop Making Sprite Animation with Circular Linked Lists Generalizing a Circular Linked List Graphs: Trees with Loops User Interface Structures A Toolkit for Building User Interfaces 337 Building the Simplest Possible Swing User Interface 338

6 Contents Building and Rendering User Interfaces 340 Building a Simple User Interface 340 Java Swing Layout Managers: GUI Tree Renderers Creating an Interactive User Interface 347 Making Our GUItree Interactive 349 Creating a Picture Tool Running from the Command Line SIMULATIONS: PROBLEM SOLVING WITH DATA STRUCTURES Using an Existing Simulation Package Introducing Simulations Overview of Greenfoot Greenfoot Basics Creating New Classes Breakout Introducing UML and Continuous Simulations Our First Model and Simulation: Wolves and Deer 387 Modeling the Wolves and Deer Modeling in Objects Implementing the Simulation Class Implementing 15.5 Implementing a Wolf 397 Deer Implementing AgentNode Extending the Simulation 404 Making Hungry Wolves 404 Writing Results to a File 407 Getting Results from a Simulation Abstracting Simulations: Creating a Simulation Package Creating a Generalized Simulation Package 413 Real Programmers Rarely Build Data Structures 414

7 Real Programmers Make Models and Choices 415 The Structure of the Simulation Package 416 Using a Li nkedli st from the Java Collection Classes Re-Making the Wolves and Deer with Our Simulation Package Making a Disease Propagation Simulation 428 Exploring Scenarios in Disease Propagation Walking through the Simulation Package Finally! Making Wildebeests and Villagers 439 Going Beyond the Wildebeests 447 Discrete Event Simulation Describing a Marketplace Differences between Continuous and Discrete Event Simulations Introducing Resources Different Kinds of Random 458 Random Distributions in the World 459 Generating Different Random Distributions 460 Generating Useful Random Distributions Ordering Events by Time 469 Sorting Objects 473 Inserting into a Sorted List 474 Using a Min-Heap Implementing a Discrete Event Simulation 477 Building a Discrete Event Simulation The Final Word: The Thin Line between Structure and Behavior 493 Bibliography 497 Index 499