PHP and Algorithmic Thinking for the Complete Beginner: Learn to Think Like a Programmer

881 Pages·2014·11.98 MB·English

by  Aristides S Bouras

PHP and Algorithmic Thinking for the Complete Beginner
Kindle Edition

Copyright © by Aristides S. Bouras and Loukia V. Ainarozidou
http://www.bouraspage.com

PHP is a copyright of the PHP Group.
The following are either registered trademarks or trademarks of Microsoft
Corporation in the United States and/or other countries: Microsoft, Windows,
IntelliSense, SQL Server, VBA, Visual Basic, and Visual C#.
Oracle and Java are registered trademarks of Oracle and/or its affiliates.
Other names may be trademarks of their respective owners.

All rights reserved. No part of this book may be reproduced or transmitted in any
form or by any means, mechanical or electronic, including photocopying, recording,
or by any information storage and retrieval system, without written permission from
the authors.
Warning and Disclaimer
This book is designed to provide information about learning “Algorithmic Thinking,”
mainly through the use of PHP scripting language. Every effort has been taken to
make this book compatible with all previous releases of PHP, and it is almost certain
to be compatible with any future releases of PHP.
The information is provided on an “as is” basis. The authors shall have neither
liability nor responsibility to any person or entity with respect to any loss or
damages arising from the information contained in this book or from the use of the
files that may accompany it.
This book is dedicated to
our adorable kids, Bill and Aphrodite,
as they “force” us to become better and better every day.
Contents at a Glance
Preface………….. ............................................................................................................................ 21
Section 1 Introductory Knowledge .................................................................................... 27
Chapter 1 How a Computer Works .................................................................................... 28
Chapter 2 PHP .......................................................................................................................... 35
Chapter 3 Software Packages to Install .......................................................................... 38
Review Questions in “Introductory Knowledge” ........................................................... 48
Section 2 Getting Started with PHP ................................................................................... 49
Chapter 4 Introduction to Basic Algorithmic Concepts .............................................. 50
Chapter 5 Variables and Constants .................................................................................. 65
Chapter 6 Handling Input and Output ............................................................................. 76
Chapter 7 Operators .............................................................................................................. 83
Chapter 8 Trace Tables ......................................................................................................... 98
Chapter 9 Using NetBeans IDE .......................................................................................... 107
Review Questions in “Getting Started with PHP” ........................................................ 123
Section 3 Sequence Control Structures .......................................................................... 125
Chapter 10 Introduction to Sequence Control Structures ....................................... 126
Chapter 11 Manipulating Numbers ................................................................................ 135
Chapter 12 Complex Mathematical Expressions ........................................................ 145
Chapter 13 Exercises with a Quotient and a Remainder ......................................... 152
Chapter 14 Manipulating Strings .................................................................................... 163
Review Questions in “Sequence Control Structures” ................................................. 177
Section 4 Decision Control Structures ............................................................................ 178
Chapter 15 Introduction to Decision Control Structures ......................................... 179
Chapter 16 The Single-Alternative Decision Structure ............................................ 195
Chapter 17 The Dual-Alternative Decision Structure ............................................... 205
Chapter 18 The Multiple-Alternative Decision Structure ........................................ 218
Chapter 19 The Case Decision Structure ....................................................................... 227
Chapter 20 Nested Decision Control Structures .......................................................... 237
Chapter 21 Tips and Tricks with Decision Control Structures ............................... 250
Chapter 22 Flowcharts with Decision Control Structures ....................................... 295
Chapter 23 More Exercises with Decision Control Structures ................................ 318
Review Questions in “Decision Control Structures” ................................................... 364
Section 5 Loop Control Structures ................................................................................... 365
Chapter 24 Introduction to Loop Control Structures ................................................ 366
Chapter 25 The Pre-Test Loop Structure ....................................................................... 371
Chapter 26 The Post-Test Loop Structure ..................................................................... 388
Chapter 27 Counted Loop Structures ............................................................................. 403
Chapter 28 Nested Loop Control Structures ................................................................. 424
Chapter 29 Tips and Tricks with Loop Control Structures ...................................... 438
Chapter 30 Flowcharts with Loop Control Structures .............................................. 488
Chapter 31 More Exercises with Loop Control Structures ....................................... 514
Review Questions in “Loop Control Structures” .......................................................... 575
Section 6 Arrays ...................................................................................................................... 577
Chapter 32 Introduction to Arrays .................................................................................. 578
Chapter 33 One-Dimensional Arrays ............................................................................. 587
Chapter 34 Two-Dimensional Arrays ............................................................................. 604
Chapter 35 Tips and Tricks with Arrays ....................................................................... 632
Chapter 36 Flowcharts with Arrays ................................................................................ 654
Chapter 37 More Exercises with Arrays ........................................................................ 668
Review Questions in “Arrays” ........................................................................................... 767
Section 7 Subprograms ........................................................................................................ 769
Chapter 38 Introduction to Subprograms .................................................................... 770
Chapter 39 User-Defined Functions ................................................................................ 774
Chapter 40 User-Defined Procedures ............................................................................. 788
Chapter 41 Tips and Tricks with Subprograms .......................................................... 800
Chapter 42 Flowcharts with Subprograms .................................................................. 838
Chapter 43 More Exercises with Subprograms ........................................................... 855
Review Questions in “Subprograms” .............................................................................. 874
Index.............................................................................................................................................. 875
Table of Contents
Preface………….. ............................................................................................................................ 21
About the Authors ................................................................................................................................. 22
Acknowledgments ................................................................................................................................. 23
How This Book is Organized ............................................................................................................. 23
Who Should Buy This Book? ............................................................................................................. 23
Where to Find Answers to Review Questions and Exercises ............................................. 24
How to Report Errata........................................................................................................................... 24
Conventions Used in This Book ....................................................................................................... 25
Section 1 Introductory Knowledge .................................................................................... 27
Chapter 1 How a Computer Works .................................................................................... 28
1.1 Introduction ............................................................................................................................. 29
1.2 What is Hardware? ................................................................................................................ 29
1.3 What is Software? .................................................................................................................. 30
1.4 How a Computer Executes (Runs) a Program ........................................................... 30
1.5 Compilers and Interpreters ............................................................................................... 30
1.6 What is Source Code? ........................................................................................................... 31
1.7 Review Questions: True/False ......................................................................................... 31
1.8 Review Questions: Multiple Choice ............................................................................... 32
Chapter 2 PHP .......................................................................................................................... 35
2.1 What is PHP? ............................................................................................................................ 36
2.2 What is the Difference Between a Script and a Program? ................................... 36
2.3 Why You Should Learn PHP .............................................................................................. 36
2.4 How PHP Works ..................................................................................................................... 37
Chapter 3 Software Packages to Install .......................................................................... 38
3.1 XAMPP ........................................................................................................................................ 39
3.2 How to Set Up XAMPP .......................................................................................................... 39
3.3 NetBeans .................................................................................................................................... 41
3.4 How to Set Up NetBeans IDE ............................................................................................ 42
Review Questions in “Introductory Knowledge” ........................................................... 48
Section 2 Getting Started with PHP ................................................................................... 49
Chapter 4 Introduction to Basic Algorithmic Concepts .............................................. 50
4.1 What is an Algorithm? ......................................................................................................... 51
4.2 The Algorithm for Making a Cup of Tea ....................................................................... 51
4.3 Properties of an Algorithm ................................................................................................ 51
4.4 Okay About Algorithms. But What is a Computer Program Anyway? ............ 52
4.5 The Party of Three! ............................................................................................................... 52
4.6 The Three Main Stages Involved in Creating an Algorithm ................................ 52
4.7 Flowcharts ................................................................................................................................ 53
Exercise 4.7-1 Finding the Average Value of Three Numbers ...................................... 55
4.8 What are ”Reserved Words”? ........................................................................................... 56
4.9 What is the Difference Between a Statement and a Command? ....................... 57
4.10 What is Structured Programming? ................................................................................ 57
4.11 The Three Fundamental Control Structures .............................................................. 57
Exercise 4.11-1 Understanding Control Structures Using Flowcharts ........................ 58
4.12 Your First PHP Script ........................................................................................................... 59
4.13 What is the Difference Between Syntax Errors and Logic Errors? .................. 59
4.14 Commenting Your Code ...................................................................................................... 60
4.15 User-Friendly Programs and Scripts ............................................................................. 61
4.16 Review Questions: True/False ......................................................................................... 61
4.17 Review Questions: Multiple Choice ............................................................................... 63
Chapter 5 Variables and Constants .................................................................................. 65
5.1 What is a Variable? ................................................................................................................ 66
5.2 What is a Constant? ............................................................................................................... 68
5.3 How Many Types of Variables and Constants Exist in PHP? .............................. 71
5.4 Rules for Naming Variables in PHP ................................................................................ 71
5.5 Rules for Naming Constants in PHP ............................................................................... 72
5.6 What Does the Phrase “Declare a Variable” Mean? ................................................ 72
5.7 How to Declare Variables in PHP .................................................................................... 73
5.8 How to Declare Constants in PHP ................................................................................... 73
5.9 Review Questions: True/False ......................................................................................... 73
5.10 Review Questions: Multiple Choice ............................................................................... 74
5.11 Review Exercises.................................................................................................................... 75
Chapter 6 Handling Input and Output ............................................................................. 76
6.1 Which Statement Outputs Messages and Results on a User’s Screen? .......... 77
6.2 How to Output Special Characters ................................................................................. 78
6.3 Which Statement Lets the User Enter Data? .............................................................. 80
6.4 Review Questions: True/False ......................................................................................... 82
6.5 Review Questions: Multiple Choice ............................................................................... 82
Chapter 7 Operators .............................................................................................................. 83
7.1 The Value Assignment Operator ..................................................................................... 84
7.2 Arithmetic Operators ........................................................................................................... 86
7.3 What is the Precedence of Arithmetic Operators? .................................................. 87
7.4 Compound Assignment Operators ................................................................................. 88
Exercise 7.4-1 Which PHP Statements are Syntactically Correct? .............................. 89
Exercise 7.4-2 Finding Variable Types ..................................................................................... 90
7.5 Incrementing/Decrementing Operators ..................................................................... 90
7.6 String Operators ..................................................................................................................... 91
Exercise 7.6-1 Concatenating Names ........................................................................................ 92
7.7 Review Questions: True/False ......................................................................................... 92
7.8 Review Questions: Multiple Choice ............................................................................... 93
7.9 Review Exercises.................................................................................................................... 95
Chapter 8 Trace Tables ......................................................................................................... 98
8.1 What is a Trace Table? ......................................................................................................... 99
Exercise 8.1-1 Creating a Trace Table ....................................................................................100
Exercise 8.1-2 Swapping Values of Variables .....................................................................100
Exercise 8.1-3 Swapping Values of Variables – A Second Approach .......................103
Exercise 8.1-4 Creating a Trace Table ....................................................................................103
Exercise 8.1-5 Creating a Trace Table ....................................................................................104
8.2 Review Questions: True/False ...................................................................................... 105
8.3 Review Exercises................................................................................................................. 105
Chapter 9 Using NetBeans IDE .......................................................................................... 107
9.1 Creating a New PHP Project ........................................................................................... 108
9.2 Writing and Executing a PHP Script ........................................................................... 110
9.3 What ”Debugging” Means ................................................................................................ 114
9.4 Debugging PHP Scripts with NetBeans IDE ............................................................ 114
9.5 Review Exercises................................................................................................................. 121
Review Questions in “Getting Started with PHP” ........................................................ 123
Section 3 Sequence Control Structures .......................................................................... 125
Chapter 10 Introduction to Sequence Control Structures ....................................... 126
10.1 What is the Sequence Control Structure? ................................................................ 127
Exercise 10.1-1 Calculating the Area of a Parallelogram .................................................127
Exercise 10.1-2 Calculating the Area of a Circle ...................................................................128
Exercise 10.1-3 Calculating Fuel Economy .............................................................................128
Exercise 10.1-4 Where is the Car? Calculating Distance Traveled ..............................129
Exercise 10.1-5 Kelvin to Fahrenheit ........................................................................................130
Exercise 10.1-6 Calculating Sales Tax........................................................................................131
Exercise 10.1-7 Calculating a Sales Discount .........................................................................131
Exercise 10.1-8 Calculating the Sales Tax Rate and Discount ........................................132
10.2 Review Exercises................................................................................................................. 133
Chapter 11 Manipulating Numbers ................................................................................ 135
11.1 Introduction .......................................................................................................................... 136
11.2 Useful Mathematical Functions .................................................................................... 136
Exercise 11.2-1 Calculating the Distance Between Two Points ....................................140
Exercise 11.2-2 How Far Did the Car Travel? ........................................................................141
11.3 Review Questions: True/False ...................................................................................... 142
11.4 Review Questions: Multiple Choice ............................................................................ 142
11.5 Review Exercises................................................................................................................. 143
Chapter 12 Complex Mathematical Expressions ........................................................ 145
12.1 Writing Complex Mathematical Expressions ......................................................... 146
Exercise 12.1-1 Representing Mathematical Expressions in PHP ...............................146
Exercise 12.1-2 Writing a Mathematical Expression in PHP ..........................................147
Exercise 12.1-3 Writing a Complex Mathematical Expression in PHP ......................147
12.2 Review Exercises................................................................................................................. 149
Chapter 13 Exercises with a Quotient and a Remainder ......................................... 152
13.1 Introduction .......................................................................................................................... 153
Exercise 13.1-1 Calculating the Quotient and Remainder of Integer Division ......153
Exercise 13.1-2 Finding the Sum of Digits ...............................................................................154
Exercise 13.1-3 Displaying an Elapsed Time .........................................................................159
Exercise 13.1-4 Reversing a Number.........................................................................................160
13.2 Review Exercises................................................................................................................. 161
Chapter 14 Manipulating Strings .................................................................................... 163
14.1 Introduction .......................................................................................................................... 164
14.2 The Position of a Character in a String ...................................................................... 164
14.3 Retrieving an Individual Character From a String ............................................... 165
Exercise 14.3-1 Displaying a String Backwards ...................................................................166
14.4 Useful String Functions .................................................................................................... 166
Exercise 14.4-1 Switching the Order of Names ....................................................................170
Exercise 14.4-2 Creating a Login ID ...........................................................................................171
Exercise 14.4-3 Creating a Random Word ..............................................................................172
14.5 Review Questions: True/False ...................................................................................... 173
14.6 Review Questions: Multiple Choice ............................................................................ 173
14.7 Review Exercises................................................................................................................. 175
Review Questions in “Sequence Control Structures” ................................................. 177
Section 4 Decision Control Structures ............................................................................ 178
Chapter 15 Introduction to Decision Control Structures ......................................... 179
15.1 What is a Decision Control Structure? ....................................................................... 180
15.2 What is a Boolean Expression? ..................................................................................... 180
15.3 How to Write Boolean Expressions ............................................................................ 180
Exercise 15.3-1 Filling in the Table ............................................................................................181
15.4 Logical Operators and Complex Boolean Expressions ....................................... 182
15.5 What is the Order of Precedence of Logical Operators? .................................... 183
15.6 What is the Order of Precedence of Arithmetic, Comparison, and Logical
Operators? .............................................................................................................................. 183
Exercise 15.6-1 Filling in the Truth Table ...............................................................................184
Exercise 15.6-2 Calculating the Results of Complex Boolean Expressions .............185
Exercise 15.6-3 Converting English Sentences to Boolean Expressions ..................186
15.7 How to Negate Boolean Expressions ......................................................................... 188
Exercise 15.7-1 Negating Boolean Expressions ....................................................................189
15.8 Review Questions: True/False ...................................................................................... 190
15.9 Review Questions: Multiple Choice ............................................................................ 191
15.10 Review Exercises................................................................................................................. 192
Chapter 16 The Single-Alternative Decision Structure ............................................ 195
16.1 The Single-Alternative Decision Structure .............................................................. 196
Exercise 16.1-1 Trace Tables and Single-Alternative Decision Structures .............197
Exercise 16.1-2 The Absolute Value of a Number ...............................................................198
16.2 Review Questions: True/False ...................................................................................... 199
16.3 Review Questions: Multiple Choice ............................................................................ 200
16.4 Review Exercises................................................................................................................. 201
Chapter 17 The Dual-Alternative Decision Structure ............................................... 205
17.1 The Dual-Alternative Decision Structure ................................................................. 206
Exercise 17.1-1 Finding the Output Message.........................................................................206
Exercise 17.1-2 Trace Tables and Dual-Alternative Decision Structures ................207
Exercise 17.1-3 Who is the Greatest? ........................................................................................209
Exercise 17.1-4 Finding Odd and Even Numbers ................................................................211
Exercise 17.1-5 Weekly Wages .....................................................................................................212
17.2 Review Questions: True/False ...................................................................................... 213
17.3 Review Questions: Multiple Choice ............................................................................ 213
17.4 Review Exercises................................................................................................................. 214
Chapter 18 The Multiple-Alternative Decision Structure ........................................ 218
18.1 The Multiple-Alternative Decision Structure ......................................................... 219
Exercise 18.1-1 Trace Tables and Multiple-Alternative Decision Structures ........220
Exercise 18.1-2 Counting the Digits ...........................................................................................222
18.2 Review Questions: True/False ...................................................................................... 223
18.3 Review Exercises................................................................................................................. 224
Chapter 19 The Case Decision Structure ....................................................................... 227
19.1 The Case Decision Structure .......................................................................................... 228
Exercise 19.1-1 The Days of the Week ......................................................................................230
19.2 Review Questions: True/False ...................................................................................... 232
19.3 Review Exercises................................................................................................................. 233
Chapter 20 Nested Decision Control Structures .......................................................... 237
20.1 What are Nested Decision Control Structures? ..................................................... 238
Exercise 20.1-1 Trace Tables and Nested Decision Control Structures ....................239
Exercise 20.1-2 Positive, Negative or Zero? ...........................................................................241
20.2 A Mistake That You Will Probably Make! ................................................................. 242
20.3 Review Questions: True/False ...................................................................................... 246
20.4 Review Exercises................................................................................................................. 246
Chapter 21 Tips and Tricks with Decision Control Structures ............................... 250
21.1 Introduction .......................................................................................................................... 251
21.2 Choosing a Decision Control Structure ..................................................................... 251
21.3 Streamlining the Decision Control Structure ......................................................... 251
Exercise 21.3-1 “Shrinking” the Algorithm .............................................................................253
Exercise 21.3-2 “Shrinking” the PHP Script ............................................................................254
Exercise 21.3-3 “Shrinking” the Algorithm .............................................................................255
21.4 Logical Operators – to Use, or not to Use: That is the Question!.................... 258
Exercise 21.4-1 Rewriting the Code ...........................................................................................259
Exercise 21.4-2 Rewriting the Code ...........................................................................................260
21.5 Merging Two or More Single-Alternative Decision Structures ...................... 261
Exercise 21.5-1 Merging the Decision Control Structures ..............................................262
Exercise 21.5-2 Merging the Decision Control Structures ..............................................263
21.6 Replacing Two Single-Alternative Decision Structures with a Dual-
Alternative One .................................................................................................................... 265
Exercise 21.6-1 “Merging” the Decision Control Structures ...........................................266
21.7 Put the Boolean Expressions Most Likely to be True First............................... 267
Exercise 21.7-1 Rearranging the Boolean Expressions ....................................................268
21.8 Converting a Case Decision Structure to a Multiple-Alternative Decision
Structure, and Vice Versa ................................................................................................ 269
Exercise 21.8-1 Converting the PHP Script .............................................................................270
Exercise 21.8-2 Converting the PHP Script .............................................................................271
Exercise 21.8-3 Converting the PHP Script .............................................................................273
21.9 Converting a Multiple-Alternative Decision Structure to Nested Decision
Control Structures, and Vice Versa ............................................................................. 273
Exercise 21.9-1 Converting the PHP Script .............................................................................274
Exercise 21.9-2 Converting the PHP Script .............................................................................276
21.10 Converting a Case Decision Structure to Nested Decision Control
Structures, and Vice Versa .............................................................................................. 277
Exercise 21.10-1 Converting the PHP Script .............................................................................278
Exercise 21.10-2 Converting the PHP Script .............................................................................279
21.11 What is Code Indentation and Why is it so Important? ..................................... 280
21.12 Using the “From Inner to Outer” Method in Decision Control Structures . 281
21.13 Review Questions: True/False ...................................................................................... 283
21.14 Review Questions: Multiple Choice ............................................................................ 284
21.15 Review Exercises................................................................................................................. 287
Chapter 22 Flowcharts with Decision Control Structures ....................................... 295
22.1 Introduction .......................................................................................................................... 296
22.2 Converting PHP Scripts to Flowcharts ...................................................................... 296
Exercise 22.2-1 Designing the Flowchart ................................................................................297
Exercise 22.2-2 Designing the Flowchart ................................................................................298
Exercise 22.2-3 Designing the Flowchart ................................................................................299
Exercise 22.2-4 Designing the Flowchart ................................................................................301
22.3 Converting Flowcharts to PHP Scripts ...................................................................... 302
Exercise 22.3-1 Writing the PHP Script ....................................................................................303
Exercise 22.3-2 Writing the PHP Script ....................................................................................305
Exercise 22.3-3 Writing the PHP Script ....................................................................................306