THINK LIKE CREATIVE PROBLEM SOLVING V. ANTON SPRAUL

Transcription

1 THINK LIKE A PROGRAMMERA A N I N T R O D U C T I O N T O CREATIVE PROBLEM SOLVING V. ANTON SPRAUL CODE EAT SLEEP

2 CONTENTS IN DETAIL ACKNOWLEDGMENTS xi INTRODUCTION xiii About This Book... xv Prerequisites... xv Chosen Topics... xv Programming Style... xvi Exercises... xvi Why C++?...xvii 1 STRATEGIES FOR PROBLEM SOLVING 1 Classic Puzzles... 2 The Fox, the Goose, and the Corn... 3 Problem: How to Cross the River?... 3 Sliding Tile Puzzles... 7 Problem: The Sliding Eight... 7 Problem: The Sliding Five... 8 Sudoku Problem: Completing a Sudoku Square The Quarrasi Lock Problem: Opening the Alien Lock General Problem-Solving Techniques Always Have a Plan Restate the Problem Divide the Problem Start with What You Know Reduce the Problem Look for Analogies Experiment Don t Get Frustrated Exercises PURE PUZZLES 25 Review of C++ Used in This Chapter Output Patterns Problem: Half of a Square Problem: A Square (Half of a Square Reduction) Problem: A Line (Half of a Square Further Reduction) Problem: Count Down by Counting Up Problem: A Sideways Triangle Input Processing Problem: Luhn Checksum Validation Breaking Down the Problem... 33

3 Problem: Convert Character Digit to Integer Problem: Luhn Checksum Validation, Fixed Length Problem: Simple Checksum Validation, Fixed Length Problem: Positive or Negative Putting the Pieces Together Tracking State Problem: Decode a Message Problem: Reading a Number with Three or Four Digits Problem: Reading a Number with Three or Four Digits, Further Simplified Conclusion Exercises SOLVING PROBLEMS WITH ARRAYS 55 Review of Array Fundamentals Store Copy Retrieval and Search Sort Compute Statistics Solving Problems with Arrays Problem: Finding the Mode Refactoring Arrays of Fixed Data Non-scalar Arrays Multidimensional Arrays Deciding When to Use Arrays Exercises SOLVING PROBLEMS WITH POINTERS AND DYNAMIC MEMORY 81 Review of Pointer Fundamentals Benefits of Pointers Runtime-Sized Data Structures Resizable Data Structures Memory Sharing When to Use Pointers Memory Matters The Stack and the Heap Memory Size Lifetime Solving Pointer Problems Variable-Length Strings Problem: Variable-Length String Manipulation Linked Lists Problem: Tracking an Unknown Quantity of Student Records Conclusion and Next Steps Exercises viii

4 5 SOLVING PROBLEMS WITH CLASSES 111 Review of Class Fundamentals Goals of Class Use Encapsulation Code Reuse Dividing the Problem Information Hiding Readability Expressiveness Building a Simple Class Problem: Class Roster The Basic Class Framework Support Methods Classes with Dynamic Data Problem: Tracking an Unknown Quantity of Student Records Adding a Node Rearranging the List Destructor Deep Copy The Big Picture for Classes with Dynamic Memory Mistakes to Avoid The Fake Class Single-Taskers Exercises SOLVING PROBLEMS WITH RECURSION 143 Review of Recursion Fundamentals Head and Tail Recursion Problem: How Many Parrots? Approach Approach Problem: Who s Our Best Customer? Approach Approach The Big Recursive Idea Problem: Computing the Sum of an Array of Integers Common Mistakes Too Many Parameters Global Variables Applying Recursion to Dynamic Data Structures Recursion and Linked Lists Problem: Counting Negative Numbers in a Singly Linked List Recursion and Binary Trees Problem: Find the Largest Value in a Binary Tree Wrapper Functions Problem: Find the Number of Leaves in a Binary Tree When to Choose Recursion Arguments Against Recursion ix

5 Problem: Display a Linked List in Order Problem: Display a Linked List in Reverse Order Exercises SOLVING PROBLEMS WITH CODE REUSE 171 Good Reuse and Bad Reuse Review of Component Fundamentals Code Block Algorithms Patterns Abstract Data Types Libraries Building Component Knowledge Exploratory Learning Problem: The First Student As-Needed Learning Problem: Efficient Traversal Choosing a Component Type Component Choice in Action Problem: Sorting Some, Leaving Others Alone Comparing the Results Exercises THINKING LIKE A PROGRAMMER 195 Creating Your Own Master Plan Playing to Your Strengths and Weaknesses Putting the Master Plan Together Tackling Any Problem Problem: Cheating at Hangman Finding a Way to Cheat Required Operations for Cheating at Hangman Initial Design Initial Coding Analysis of Initial Results The Art of Problem Solving Learning New Programming Skills New Languages New Skills for a Language You Already Know New Libraries Take a Class Conclusion Exercises INDEX 227 x