Think Like a Programmer: Practical Java solutions for students, developers, and interview preparation

Cover....2

Title Page....3

Copyright Page....4

Dedication Page....5

About the Author....6

About the Reviewers....7

Acknowledgement....9

Preface....10

Table of Contents....15

Section I: Beginner Problems....26

1. Simple Loops....27

Introduction....27

Structure....28

Objectives....28

Program 1.1: Print the contents of an array....29

Algorithm....29

Flowchart....29

Java code....29

Code explanation....30

Program 1.2: Reverse and print an array....30

Algorithm....30

Flowchart....31

Java code....31

Code explanation....32

Program 1.3: FizzBuzz....32

Algorithm....32

Flowchart....33

Java code....34

Code explanation....34

Program 1.4: Print a diamond of numbers....35

Algorithm....35

Flowchart....36

Java code....37

Code explanation....39

Program 1.5: Diamond outline of numbers....40

Algorithm....40

Flowchart....42

Java code....42

Code explanation....44

Program 1.6: Checking valid number using while....46

Algorithm....46

Flowchart....46

Java code....47

Code explanation....48

Program 1.7: Display user names....49

Algorithm....49

Flowchart....50

Java code....50

Code explanation....51

Conclusion....51

Points to remember....52

Questions....52

2. File Operations....54

Introduction....54

Structure....54

Objectives....54

Program 2.1: Write to a text file....55

Algorithm....55

Flowchart....56

Java code....56

Code explanation....57

Program 2.2: Read and print from a text file....58

Algorithm....58

Flowchart....58

Java code....59

Code explanation....60

Program 2.3: Read and print from a CSV file....61

Algorithm....61

Flowchart....62

Java code....62

Code explanation....64

Program 2.4: Write a password file....65

Algorithm....66

Flowchart....66

Java code....67

Code explanation....68

Program 2.5: Validate a user from a password file....69

Algorithm....70

Flowchart....71

Java code....71

Code explanation....73

Program 2.6: Write a unique password file....75

Algorithm....76

Flowchart....77

Java code....78

Code explanation....80

Conclusion....82

Points to remember....82

Questions....83

3. Characters and Strings....84

Introduction....84

Structure....84

Objectives....85

Exploring instance and static methods....85

Program 3.1: Reverse a string....86

Algorithm....86

Flowchart....86

Java code....87

Code explanation....87

Program 3.2: Check if a primitive character is uppercase....88

Algorithm....88

Flowchart....88

Java code....89

Code explanation....89

Program 3.3: Check if a reference character is uppercase....90

Algorithm....90

Flowchart....90

Java code....91

Code explanation....91

Program 3.4: Format a phone number....92

Algorithm....92

Flowchart....92

Java code....93

Code explanation....94

Program 3.5: Check if a state code is valid....95

Algorithm....95

Flowchart....96

Java code....96

Code explanation....97

Program 3.6: Check if a state code is valid using regular expression....98

Algorithm....98

Flowchart....98

Java code....99

Code explanation....99

Program 3.7: Check if a string is a palindrome....100

Algorithm....101

Flowchart....101

Java code....102

Code explanation....102

Program 3.8: Parse and format hockey team data....103

Algorithm....104

Flowchart....105

Java code....106

Code explanation....107

Conclusion....108

Points to remember....109

Questions....110

Section 2: Intermediate Problems....111

4. Arithmetic Solutions....112

Introduction....112

Structure....112

Objectives....113

Program 4.1: Multiply two numbers....113

Algorithm....113

Flowchart....114

Java code....114

Code explanation....115

Program 4.2: Subtract two numbers....116

Algorithm....117

Flowchart....117

Java code....118

Code explanation....118

Program 4.3: Divide two numbers....119

Algorithm....119

Flowchart....120

Java code....122

Code explanation....123

Program 4.4: Check if a number is a power of two....124

Algorithm....124

Flowchart....125

Java code....126

Code explanation....127

Program 4.5: Build a binary error handler....128

Algorithm....128

Flowchart....128

Java code....131

Code explanation....133

Conclusion....135

Points to remember....135

Questions....136

5. Basic Data Structures....137

Introduction....137

Structure....137

Objectives....138

Program 5.1: Build a stack to process truck pallets....138

Algorithm....139

Flowchart....140

Java code....143

Code explanation....144

Program 5.2: Build a queue for airport takeoffs....145

Algorithm....146

Flowchart....147

Java code....150

Code explanation....151

Program 5.3: Build a linked list for navigation....153

Algorithm....154

Flowchart....155

Java code....156

Code explanation....158

Conclusion....160

Points to remember....161

Questions....161

6. Pattern Matching....163

Introduction....163

Structure....164

Objectives....164

Program 6.1: Determine a valid phone number....164

Algorithm....165

Flowchart....166

Java code....166

Code explanation....167

Program 6.2: Determine if a new password is valid....169

Algorithm....170

Flowchart....170

Java code....171

Code explanation....171

Program 6.3: Determine if an IP address is valid....172

Algorithm....174

Flowchart....174

Java code....175

Code explanation....175

Program 6.4: Compute tollway charges by vehicle....177

Algorithm....178

Flowchart....180

Java code....181

Code explanation....184

Conclusion....186

Points to remember....187

Questions....187

Section 3: Challenging Problems....189

7. Complex Data Structures....190

Introduction....190

Structure....190

Objectives....190

Program 7.1: Build a linked list for browser history....191

Algorithm....193

Flowchart....195

Java code....197

Code explanation....200

Program 7.2: Build a binary tree to store fruit data....202

Algorithm....203

Flowchart....205

Java code....206

Code explanation....209

Program 7.3: Build a heap for a medical queue....212

Algorithm....214

Flowchart....216

Java code....218

Code explanation....220

Conclusion....223

Points to remember....224

Questions....224

8. Sorting....226

Introduction....226

Structure....226

Objectives....226

Program 8.1: Sort users with a bubble sort....227

Algorithm....228

Flowchart....229

Java code....229

Code explanation....230

Program 8.2: Sort users with a merge sort....232

Algorithm....233

Flowchart....235

Java code....237

Code explanation....238

Program 8.3: Sort with a binary tree sort....240

Algorithm....241

Flowchart....244

Java code....245

Code explanation....249

Conclusion....252

Points to remember....253

Questions....253

9. Graphics....255

Introduction....255

Structure....255

Objectives....256

Program 9.1: Draw the moon with a starfield....256

Algorithm....257

Flowchart....259

Java code....259

Code explanation....261

Program 9.2: Animate a bouncing ball....262

Algorithm....263

Flowchart....266

Java code....268

Code explanation....272

Program 9.3: Animate multiple bouncing balls....275

Algorithm....276

Flowchart....280

Java code....281

Code explanation....286

Conclusion....288

Points to remember....289

Questions....289

APPENDIX A: References....291

APPENDIX B: Answers to Exercises....293

Chapter 1....294

Chapter 2....296

Chapter 3....297

Chapter 4....299

Chapter 5....302

Chapter 6....305

Chapter 7....307

Chapter 8....311

Chapter 9....312

Index....314

Java is the backbone of modern enterprise software, and mastering its logic is the first step toward becoming a professional developer. This book offers a selection of curated questions, ranging from foundational topics to advanced programming concepts.

By the end of this book, you will be competent in applying decision constructs to diverse programming challenges and possess a solid understanding of algorithmic efficiency. Through hands-on experience and real-world problems, this book ensures that learners develop the problem-solving skills necessary for success as a software developer.

What you will learn

• Approaches to solving common programming problems.
• Execute advanced string parsing and character identification through decision logic.
• Solve complex operations utilizing recursive functions and mathematical logic constructs.
• Develop systematic problem-solving skills for complex backend data processing tasks.
• Develop logic and problem-solving skills incrementally.

Who this book is for

This book is for students, educators, and developers seeking to improve their programming logic. Readers should have basic Java syntax knowledge to solve problems involving recursion and data structures. It is ideal for candidates preparing for technical exams and professional interviews.