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PHP and Algorithmic Thinking for the Complete Beginner

Name: PHP and Algorithmic Thinking for the Complete Beginner
Author: Aristides Bouras
ISBN: 9781836209379

by Aristides Bouras

June 2024

Beginner

938 pages

15h 59m

English

Packt Publishing

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Table of Contents
Preface
About the Author
Acknowledgments
How This Book is OrganizedWho Should Buy This Book?
Conventions Used in This Book
How to Report ErrataWhere to Download Material About this BookIf you Like this Book
Part I Introductory Knowledge
Chapter 1 How a Computer Works
1.1 Introduction1.2 What is Hardware?1.3 What is Software?1.4 How a Computer Executes (Runs) a Program1.5 Compilers and Interpreters1.6 What is Source Code?1.7 Review Questions: True/False1.8 Review Questions: Multiple Choice
Chapter 2 PHP and Integrated Development Environments
2.1 What is PHP?2.2 What is the Difference Between a Script and a Program?2.3 Why You Should Learn PHP2.4 How PHP Works2.5 Integrated Development Environments2.6 Visual Studio
Chapter 3 Software Packages to Install
3.1 What to Install
Review in “Introductory Knowledge”
Review Crossword PuzzlesReview Questions

Part II Getting Started with PHP
Chapter 4 Introduction to Basic Algorithmic Concepts
4.1 What is an Algorithm?4.2 The Algorithm for Making a Cup of Tea4.3 Properties of an Algorithm4.4 Okay About Algorithms. But What is a Computer Program Anyway?4.5 The Three Parties!4.6 The Three Main Stages Involved in Creating an Algorithm4.7 FlowchartsExercise 4.7-1 Finding the Average Value of Three Numbers4.8 What are ”Reserved Words”?4.9 What is the Difference Between a Statement and a Command?4.10 What is Structured Programming?4.11 The Three Fundamental Control StructuresExercise 4.11-1 Understanding Control Structures Using Flowcharts4.12 Your First PHP Script4.13 What is the Difference Between a Syntax Error, a Logic Error, and a Runtime Error?4.14 What “Debugging” Means4.15 Commenting Your Code4.16 User-Friendly Programs and Scripts4.17 Review Questions: True/False4.18 Review Questions: Multiple Choice
Chapter 5 Variables and Constants
5.1 What is a Variable?5.2 What is a Constant?5.3 How Many Types of Variables and Constants Exist?5.4 Rules and Conventions for Naming Variables and Constants in PHP5.5 What Does the Phrase “Declare a Variable” Mean?5.6 How to Declare Variables in PHP5.7 How to Declare Constants in PHP5.8 Review Questions: True/False5.9 Review Questions: Multiple Choice5.10 Review Exercises
Chapter 6 Handling Input and Output
6.1 How to Output Messages and Results to a User's Screen?6.2 How to Output Special Characters?6.3 How to Prompt the User to Enter Data?6.4 Review Questions: True/False6.5 Review Questions: Multiple Choice
Chapter 7 Operators
7.1 The Value Assignment Operator7.2 Arithmetic Operators7.3 What is the Precedence of Arithmetic Operators?7.4 Compound Assignment OperatorsExercise 7.4-1 Which PHP Statements are Syntactically Correct?Exercise 7.4-2 Finding Variable Types7.5 Incrementing/Decrementing Operators7.6 String OperatorsExercise 7.6-1 Concatenating Names7.7 Review Questions: True/False7.8 Review Questions: Multiple Choice7.9 Review Exercises
Chapter 8 Trace Tables
8.1 What is a Trace Table?Exercise 8.1-1 Creating a Trace TableExercise 8.1-2 Creating a Trace TableExercise 8.1-3 Swapping Values of VariablesExercise 8.1-4 Swapping Values of Variables – An Alternative Approach8.2 Review Questions: True/False8.3 Review Exercises
Chapter 9 Using Visual Studio Code
9.1 Write, Execute and Debug PHP Scripts
Review in “Getting Started with PHP”
Review Crossword PuzzlesReview Questions
Part III Sequence Control Structures
Chapter 10 Introduction to Sequence Control Structures
10.1 What is the Sequence Control Structure?Exercise 10.1-1 Calculating the Area of a RectangleExercise 10.1-2 Calculating the Area of a CircleExercise 10.1-3 Where is the Car? Calculating Distance TraveledExercise 10.1-4 Kelvin to FahrenheitExercise 10.1-5 Calculating Sales TaxExercise 10.1-6 Calculating a Sales DiscountExercise 10.1-7 Calculating a Sales Discount and Tax10.2 Review Exercises
Chapter 11 Manipulating Numbers
11.1 Introduction11.2 Useful Mathematical Functions (Subprograms), and MoreExercise 11.2-1 Calculating the Distance Between Two PointsExercise 11.2-2 How Far Did the Car Travel?11.3 Review Questions: True/False11.4 Review Questions: Multiple Choice11.5 Review Exercises
Chapter 12 Complex Mathematical Expressions
12.1 Writing Complex Mathematical ExpressionsExercise 12.1-1 Representing Mathematical Expressions in PHPExercise 12.1-2 Writing a Mathematical Expression in PHPExercise 12.1-3 Writing a Complex Mathematical Expression in PHP12.2 Review Exercises
Chapter 13 Exercises With a Quotient and a Remainder
13.1 IntroductionExercise 13.1-1 Calculating the Quotient and Remainder of Integer DivisionExercise 13.1-2 Finding the Sum of DigitsExercise 13.1-3 Displaying an Elapsed TimeExercise 13.1-4 Reversing a Number13.2 Review Exercises
Chapter 14 Manipulating Strings
14.1 Introduction14.2 The Position of a Character in a String14.3 Useful String Functions (Subprograms), and MoreExercise 14.3-1 Displaying a String BackwardsExercise 14.3-2 Switching the Order of NamesExercise 14.3-3 Creating a Login IDExercise 14.3-4 Creating a Random WordExercise 14.3-5 Finding the Sum of Digits14.4 Review Questions: True/False14.5 Review Questions: Multiple Choice14.6 Review Exercises
Review in “Sequence Control Structures”
Review Crossword PuzzleReview Questions
Part IV Decision Control Structures
Chapter 15 Making Questions
15.1 Introduction15.2 What is a Boolean Expression?15.3 How to Write Simple Boolean ExpressionsExercise 15.3-1 Filling in the Table15.4 Logical Operators and Complex Boolean ExpressionsExercise 15.4-1 Calculating the Results of Complex Boolean Expressions15.5 Assigning the Result of a Boolean Expression to a Variable15.6 What is the Order of Precedence of Logical Operators?Exercise 15.6-1 Filling in the Truth TableExercise 15.6-2 Converting English Sentences to Boolean Expressions15.7 What is the Order of Precedence of Arithmetic, Comparison, and Logical Operators?15.8 How to Negate Boolean ExpressionsExercise 15.8-1 Negating Boolean Expressions15.9 Review Questions: True/False15.10 Review Questions: Multiple Choice15.11 Review Exercises
Chapter 16 The Single-Alternative Decision Structure
16.1 The Single-Alternative Decision StructureExercise 16.1-1 Trace Tables and Single-Alternative Decision StructuresExercise 16.1-2 The Absolute Value of a Number16.2 Review Questions: True/False16.3 Review Questions: Multiple Choice16.4 Review Exercises
Chapter 17 The Dual-Alternative Decision Structure
17.1 The Dual-Alternative Decision StructureExercise 17.1-1 Finding the Output MessageExercise 17.1-2 Trace Tables and Dual-Alternative Decision StructuresExercise 17.1-3 Who is the Greatest?Exercise 17.1-4 Finding Odd and Even NumbersExercise 17.1-5 Weekly Wages17.2 Review Questions: True/False17.3 Review Questions: Multiple Choice17.4 Review Exercises
Chapter 18 The Multiple-Alternative Decision Structure
18.1 The Multiple-Alternative Decision StructureExercise 18.1-1 Trace Tables and Multiple-Alternative Decision StructuresExercise 18.1-2 Counting the Digits18.2 Review Questions: True/False18.3 Review Exercises
Chapter 19 The Case Decision Structure
19.1 The Case Decision StructureExercise 19.1-1 The Days of the Week19.2 Review Questions: True/False19.3 Review Exercises
Chapter 20 Nested Decision Control Structures
20.1 What are Nested Decision Control Structures?Exercise 20.1-1 Trace Tables and Nested Decision Control StructuresExercise 20.1-2 Positive, Negative or Zero?20.2 Review Questions: True/False20.3 Review Exercises
Chapter 21 More about Flowcharts with Decision Control Structures
21.1 Introduction21.2 Converting PHP scripts to FlowchartsExercise 21.2-1 Designing the FlowchartExercise 21.2-2 Designing the FlowchartExercise 21.2-3 Designing the Flowchart21.3 A Mistake That You Will Probably Make!21.4 Converting Flowcharts to PHP scriptsExercise 21.4-1 Writing the PHP ScriptExercise 21.4-2 Writing the PHP ScriptExercise 21.4-3 Writing the PHP Script21.5 Review Exercises
Chapter 22 Tips and Tricks with Decision Control Structures
22.1 Introduction22.2 Choosing a Decision Control Structure22.3 Streamlining the Decision Control StructureExercise 22.3-1 “Shrinking” the AlgorithmExercise 22.3-2 “Shrinking” the PHP scriptExercise 22.3-3 “Shrinking” the Algorithm22.4 Logical Operators – to Use, or not to Use: That is the Question!Exercise 22.4-1 Rewriting the CodeExercise 22.4-2 Rewriting the Code22.5 Merging Two or More Single-Alternative Decision StructuresExercise 22.5-1 Merging the Decision Control StructuresExercise 22.5-2 Merging the Decision Control Structures22.6 Replacing Two Single-Alternative Decision Structures with a Dual-Alternative OneExercise 22.6-1 “Merging” the Decision Control Structures22.7 Put the Boolean Expressions Most Likely to be True FirstExercise 22.7-1 Rearranging the Boolean Expressions22.8 Why is Code Indentation so Important?22.9 Review Questions: True/False22.10 Review Questions: Multiple Choice22.11 Review Exercises
Chapter 23 More with Decision Control Structures
23.1 Simple Exercises with Decision Control StructuresExercise 23.1-1 Is it an Integer?Exercise 23.1-2 Validating Data Input and Finding Odd and Even NumbersExercise 23.1-3 Where is the Tollkeeper?Exercise 23.1-4 The Most Scientific Calculator Ever!Exercise 23.1-5 Converting Gallons to Liters, and Vice VersaExercise 23.1-6 Converting Gallons to Liters, and Vice Versa (with Data Validation)23.2 Finding Minimum and Maximum Values with Decision Control StructuresExercise 23.2-1 Finding the Name of the Heaviest Person23.3 Decision Control Structures in Solving Mathematical ProblemsExercise 23.3-1 Finding the Value of yExercise 23.3-2 Finding the Values of yExercise 23.3-3 Solving the Linear Equation ax + b = 0Exercise 23.3-4 Solving the Quadratic Equation ax2 + bx + c = 023.4 Exercises with Series of Consecutive Ranges of ValuesExercise 23.4-1 Calculating the DiscountExercise 23.4-2 Validating Data Input and Calculating the DiscountExercise 23.4-3 Sending a ParcelExercise 23.4-4 Finding the Values of yExercise 23.4-5 Progressive Rates and Electricity ConsumptionExercise 23.4-6 Progressive Rates and Text Messaging Services23.5 Exercises of a General Nature with Decision Control StructuresExercise 23.5-1 Finding a Leap YearExercise 23.5-2 Displaying the Days of the MonthExercise 23.5-3 Checking for Proper Capitalization and PunctuationExercise 23.5-4 Is the Number a Palindrome?23.6 Boolean Expressions Reference and Handy Tips23.7 Review Exercises
Review in “Decision Control Structures”
Review Crossword PuzzleReview Questions
Part V Loop Control Structures
Chapter 24 Introduction to Loop Control Structures
24.1 What is a Loop Control Structure?24.2 From Sequence Control to Loop Control Structures24.3 Review Questions: True/False
Chapter 25 Pre-Test, Mid-Test and Post-Test Loop Structures
25.1 The Pre-Test Loop StructureExercise 25.1-1 Designing the Flowchart and Counting the Total Number of IterationsExercise 25.1-2 Counting the Total Number of IterationsExercise 25.1-3 Counting the Total Number of IterationsExercise 25.1-4 Counting the Total Number of IterationsExercise 25.1-5 Finding the Sum of Four NumbersExercise 25.1-6 Finding the Sum of Odd NumbersExercise 25.1-7 Finding the Sum of N NumbersExercise 25.1-8 Finding the Sum of an Unknown Quantity of NumbersExercise 25.1-9 Finding the Product of 20 Numbers25.2 The Post-Test Loop StructureExercise 25.2-1 Designing the Flowchart and Counting the Total Number of IterationsExercise 25.2-2 Counting the Total Number of IterationsExercise 25.2-3 Designing the Flowchart and Counting the Total Number of IterationsExercise 25.2-4 Counting the Total Number of IterationsExercise 25.2-5 Finding the Product of N Numbers25.3 The Mid-Test Loop StructureExercise 25.3-1 Designing the Flowchart and Counting the Total Number of Iterations25.4 Review Questions: True/False25.5 Review Questions: Multiple Choice25.6 Review Exercises
Chapter 26 Definite Loops
26.1 The for statementExercise 26.1-1 Creating the Trace TableExercise 26.1-2 Creating the Trace TableExercise 26.1-3 Counting the Total Number of IterationsExercise 26.1-4 Finding the Sum of Four NumbersExercise 26.1-5 Finding the Square Roots from 0 to NExercise 26.1-6 Finding the Sum of 1 + 2 + 3 + … + 100Exercise 26.1-7 Finding the Product of 2 × 4 × 6 × 8 × 10Exercise 26.1-8 Finding the Sum of 22 + 42 + 62 + … (2N)2Exercise 26.1-9 Finding the Sum of 33 + 66 + 99 + … (3N)3NExercise 26.1-10 Finding the Average Value of Positive NumbersExercise 26.1-11 Counting the Vowels26.2 Rules that Apply to For-LoopsExercise 26.2-1 Counting the Total Number of IterationsExercise 26.2-2 Counting the Total Number of IterationsExercise 26.2-3 Counting the Total Number of IterationsExercise 26.2-4 Counting the Total Number of IterationsExercise 26.2-5 Finding the Sum of N Numbers26.3 Review Questions: True/False26.4 Review Questions: Multiple Choice26.5 Review Exercises
Chapter 27 Nested Loop Control Structures
27.1 What is a Nested Loop?Exercise 27.1-1 Say “Hello Zeus”. Counting the Total Number of Iterations.Exercise 27.1-2 Creating the Trace Table27.2 Rules that Apply to Nested LoopsExercise 27.2-1 Violating the First RuleExercise 27.2-2 Violating the Second Rule27.3 Review Questions: True/False27.4 Review Questions: Multiple Choice27.5 Review Exercises
Chapter 28 More about Flowcharts with Loop Control Structures
28.1 Introduction28.2 Converting PHP scripts to FlowchartsExercise 28.2-1 Designing the Flowchart FragmentExercise 28.2-2 Designing the Flowchart FragmentExercise 28.2-3 Designing the FlowchartExercise 28.2-4 Designing the Flowchart FragmentExercise 28.2-5 Designing the Flowchart28.3 Converting Flowcharts to PHP scriptsExercise 28.3-1 Writing the PHP ScriptExercise 28.3-2 Writing the PHP ScriptExercise 28.3-3 Writing the PHP ScriptExercise 28.3-4 Writing the PHP Script28.4 Review Exercises
Chapter 29 Tips and Tricks with Loop Control Structures
29.1 Introduction29.2 Choosing a Loop Control Structure29.3 The “Ultimate” Rule29.4 Breaking Out of a Loop29.5 Cleaning Out Your LoopsExercise 29.5-1 Cleaning Out the LoopExercise 29.5-2 Cleaning Out the Loop29.6 Endless Loops and How to Stop Them29.7 The “From Inner to Outer” Method29.8 Review Questions: True/False29.9 Review Questions: Multiple Choice29.10 Review Exercises
Chapter 30 More with Loop Control Structures
30.1 Simple Exercises with Loop Control StructuresExercise 30.1-1 Counting the Numbers According to Which is GreaterExercise 30.1-2 Counting the Numbers According to Their DigitsExercise 30.1-3 How Many Numbers Fit in a SumExercise 30.1-4 Finding the Total Number of Positive IntegersExercise 30.1-5 Iterating as Many Times as the User WishesExercise 30.1-6 Finding the Sum of the Digits30.2 Exercises with Nested Loop Control StructuresExercise 30.2-1 Displaying all Three-Digit Integers that Contain a Given DigitExercise 30.2-2 Displaying all Instances of a Specified Condition30.3 Data Validation with Loop Control StructuresExercise 30.3-1 Finding Odd and Even Numbers - Validation Without Error MessagesExercise 30.3-2 Finding the Sum of Four Numbers30.4 Finding Minimum and Maximum Values with Loop Control StructuresExercise 30.4-1 Validating and Finding the Minimum and the Maximum ValueExercise 30.4-2 Validating and Finding the Hottest PlanetExercise 30.4-3 ”Making the Grade”30.5 Using Loop Control Structures to Solve Mathematical ProblemsExercise 30.5-1 Calculating the Area of as Many Triangles as the User WishesExercise 30.5-2 Finding x and yExercise 30.5-3 The Russian Multiplication AlgorithmExercise 30.5-4 Finding the Number of DivisorsExercise 30.5-5 Is the Number a Prime?Exercise 30.5-6 Finding all Prime Numbers from 1 to NExercise 30.5-7 Heron's Square RootExercise 30.5-8 Calculating πExercise 30.5-9 Approximating a Real with a Fraction30.6 Exercises of a General Nature with Loop Control StructuresExercise 30.6-1 Fahrenheit to Kelvin, from 0 to 100Exercise 30.6-2 Rice on a ChessboardExercise 30.6-3 Just a PollExercise 30.6-4 Is the Message a Palindrome?30.7 Review Questions: True/False30.8 Review Exercises
Review in “Loop Control Structures”
Review Crossword PuzzleReview Questions
Part VI Arrays in PHP
Chapter 31 One-Dimensional Arrays
31.1 Introduction31.2 What is an Array?Exercise 31.2-1 Designing an ArrayExercise 31.2-2 Designing ArraysExercise 31.2-3 Designing Arrays31.3 Creating One-Dimensional Arrays in PHP31.4 How to Get Values from a One-Dimensional ArrayExercise 31.4-1 Creating the Trace TableExercise 31.4-2 Using a Non-Existing Index31.5 How to Alter the Value of an Array Element31.6 How to Iterate Through a One-Dimensional ArrayExercise 31.6-1 Finding the Sum31.7 How to Add User-Entered Values to a One-Dimensional ArrayExercise 31.7-1 Displaying Words in Reverse OrderExercise 31.7-2 Displaying Positive Numbers in Reverse OrderExercise 31.7-3 Finding the Average ValueExercise 31.7-4 Displaying Reals OnlyExercise 31.7-5 Displaying Elements with Odd-Numbered IndexesExercise 31.7-6 Displaying Even Numbers in Odd–Numbered Index Positions31.8 What is an Map?31.9 Creating Associative Arrays in PHP31.10 How to Get a Value from an Associative ArrayExercise 31.10-1 Roman Numerals to NumbersExercise 31.10-2 Using a Non-Existing Key in Dictionaries31.11 How to Alter the Value of an Element of an Associative Array31.12 How to Iterate Through an Associative Array31.13 Review Questions: True/False31.14 Review Questions: Multiple Choice31.15 Review Exercises
Chapter 32 Two-Dimensional Arrays
32.1 Creating Two-Dimensional Arrays in PHP32.2 How to Get Values from Two-Dimensional ArraysExercise 32.2-1 Creating the Trace Table32.3 How to Iterate Through a Two-Dimensional Array32.4 How to Add User-Entered Values to a Two-Dimensional ArrayExercise 32.4-1 Displaying Reals OnlyExercise 32.4-2 Displaying Odd Columns Only32.5 What's the Story on Variables $i and $j?32.6 Square MatricesExercise 32.6-1 Finding the Sum of the Elements on the Main DiagonalExercise 32.6-2 Finding the Sum of the Elements on the AntidiagonalExercise 32.6-3 Filling in the Array32.7 Review Questions: True/False32.8 Review Questions: Multiple Choice32.9 Review Exercises
Chapter 33 Tips and Tricks with Arrays
33.1 Introduction33.2 Processing Each Row IndividuallyExercise 33.2-1 Finding the Average Value33.3 Processing Each Column IndividuallyExercise 33.3-1 Finding the Average Value33.4 How to Use More Than One Arrays in a ScriptExercise 33.4-1 Using Three One-Dimensional ArraysExercise 33.4-2 Using a One-Dimensional Array Along with a Two-Dimensional ArrayExercise 33.4-3 Using an Indexed Array Along with an Associative Array33.5 Creating a One-Dimensional Array from a Two-Dimensional Array33.6 Creating a Two-Dimensional Array from a One-Dimensional Array33.7 Useful Array Functions (Subprograms)33.8 Review Questions: True/False33.9 Review Questions: Multiple Choice33.10 Review Exercises
Chapter 34 More with Arrays
34.1 Simple Exercises with ArraysExercise 34.1-1 Creating an Array that Contains the Average Values of its Neighboring ElementsExercise 34.1-2 Creating an Array with the Greatest ValuesExercise 34.1-3 Merging One-Dimensional ArraysExercise 34.1-4 Creating Two Arrays – Separating Positive from Negative ValuesExercise 34.1-5 Creating an Array with Those who Contain Digit 534.2 Data Validation with ArraysExercise 34.2-1 Displaying Odds in Reverse Order34.3 Finding Minimum and Maximum Values in ArraysExercise 34.3-1 Which Depth is the Greatest?Exercise 34.3-2 Which Lake is the Deepest?Exercise 34.3-3 Which Lake, in Which Country, Having Which Average Area, is the Deepest?Exercise 34.3-4 Which Students Have got the Greatest Grade?Exercise 34.3-5 Finding the Minimum Value of a Two-Dimensional ArrayExercise 34.3-6 Finding the City with the Coldest DayExercise 34.3-7 Finding the Minimum and the Maximum Value of Each Row
34.4 Sorting Arrays
Exercise 34.4-1 The Bubble Sort Algorithm – Sorting One-Dimensional Arrays with Numeric ValuesExercise 34.4-2 Sorting One-Dimensional Arrays with Alphanumeric ValuesExercise 34.4-3 Sorting One-Dimensional Arrays While Preserving the Relationship with a Second ArrayExercise 34.4-4 Sorting Last and First NamesExercise 34.4-5 Sorting a Two-Dimensional ArrayExercise 34.4-6 The Modified Bubble Sort Algorithm – Sorting One-Dimensional ArraysExercise 34.4-7 The Selection Sort Algorithm – Sorting One-Dimensional ArraysExercise 34.4-8 Sorting One-Dimensional Arrays While Preserving the Relationship with a Second ArrayExercise 34.4-9 The Insertion Sort Algorithm – Sorting One-Dimensional ArraysExercise 34.4-10 The Three Worst Elapsed Times34.5 Searching Elements in ArraysExercise 34.5-1 The Linear Search Algorithm – Searching in a One-Dimensional Array that may Contain the Same Value Multiple TimesExercise 34.5-2 Display the Last Names of All Those People Who Have the Same First NameExercise 34.5-3 The Linear Search Algorithm – Searching in a Two-Dimensional Array that May Contain the Same Value Multiple TimesExercise 34.5-4 The Linear Search Algorithm – Searching in a One-Dimensional Array that Contains Unique ValuesExercise 34.5-5 Searching for a Social Security NumberExercise 34.5-6 The Linear Search Algorithm – Searching in a Two-Dimensional Array that Contains Unique ValuesExercise 34.5-7 Checking if a Value Exists in all ColumnsExercise 34.5-8 The Binary Search Algorithm – Searching in a Sorted One-Dimensional ArrayExercise 34.5-9 Display all the Historical Events for a CountryExercise 34.5-10 Searching in Each Column of a Two-Dimensional Array34.6 Exercises of a General Nature with ArraysExercise 34.6-1 On Which Days was There a Possibility of Snow?Exercise 34.6-2 Was There Any Possibility of Snow?Exercise 34.6-3 In Which Cities was There a Possibility of Snow?Exercise 34.6-4 Display from Highest to Lowest Grades by Student, and in Alphabetical OrderExercise 34.6-5 Archery at the Summer OlympicsExercise 34.6-6 The Five Best ScorersExercise 34.6-7 Counting the Frequency of Vowels34.7 Review Questions: True/False34.8 Review Exercises
Review in “Arrays in PHP”
Review Crossword PuzzleReview Questions
Part VII Subprograms
Chapter 35 Introduction to Subprograms
35.1 What Exactly is a Subprogram?35.2 What is Procedural Programming?35.3 What is Modular Programming?35.4 Review Questions: True/False
Chapter 36 User-Defined Subprograms
36.1 Subprograms that Return a Value36.2 How to Make a Call to a Function36.3 Subprograms that Return no Values36.4 How to Make a Call to a void Function36.5 Formal and Actual Arguments36.6 How Does a Function Execute?Exercise 36.6-1 Back to Basics – Calculating the Sum of Two NumbersExercise 36.6-2 Calculating the Sum of Two Numbers Using Fewer Lines of Code!36.7 How Does a void Function Execute?Exercise 36.7-1 Back to Basics – Displaying the Absolute Value of a Number36.8 Review Questions: True/False36.9 Review Exercises
Chapter 37 Tips and Tricks with Subprograms
37.1 Can Two Subprograms use Variables of the Same Name?37.2 Can a Subprogram Call Another Subprogram?37.3 Passing Arguments by Value and by Reference37.4 Passing and/or Returning an Array37.5 Default Argument Values (Optional Arguments) and Named Arguments37.6 The Scope of a Variable37.7 Converting Parts of Code into Subprograms37.8 Recursion37.9 Review Questions: True/False37.10 Review Exercises
Chapter 38 More with Subprograms
38.1 Simple Exercises with SubprogramsExercise 38.1-1 A Simple Currency ConverterExercise 38.1-2 Finding the Average Values of Positive IntegersExercise 38.1-3 Finding the Sum of Odd Positive IntegersExercise 38.1-4 Finding the Values of y38.2 Exercises of a General Nature with SubprogramsExercise 38.2-1 Validating Data Input Using a SubprogramExercise 38.2-2 Sorting an Array Using a SubprogramExercise 38.2-3 Progressive Rates and Electricity ConsumptionExercise 38.2-4 Roll, Roll, Roll the… Dice!Exercise 38.2-5 How Many Times Does Each Number of the Dice Appear?38.3 Review Exercises
Review in “Subprograms”
Review Crossword PuzzleReview Questions
Part VIII Object-Oriented Programming
Chapter 39 Introduction to Object-Oriented Programming
39.1 What is Object-Oriented Programming?39.2 Classes and Objects in PHP39.3 The Constructor and the Keyword $this39.4 Passing Initial Values to the ConstructorExercise 39.4-1 Historical Events39.5 Getter and Setter MethodsExercise 39.5-1 The Roman Numerals39.6 Can a Method Call Another Method of the Same Class?Exercise 39.6-1 Doing Math39.7 Class Inheritance39.8 Review Questions: True/False39.9 Review Exercises
Review in “Object-Oriented Programming”
Review Crossword PuzzleReview Questions
Part IX Files
Chapter 40 Introduction to Files
40.1 Introduction40.2 Opening a File40.3 Closing a File40.4 Writing in (or Appending to) a File40.5 The File Pointer40.6 Reading from a File40.7 Iterating Through the Contents of a File40.8 Review Questions: True/False40.9 Review Exercises
Chapter 41 More with Files
41.1 Exercises of a General Nature with FilesExercise 41.1-1 Calculating the Sum of 10 NumbersExercise 41.1-2 Calculating the Average Value of an Unknown Quantity of NumbersExercise 41.1-3 Finding Minimum and Maximum ValuesExercise 41.1-4 Concatenating FilesExercise 41.1-5 Searching in a FileExercise 41.1-6 Combining Files with Subprograms41.2 Review Exercises
Review in “Files”
Review Crossword PuzzleReview Questions
Some Final Words from the Author

Content preview from PHP and Algorithmic Thinking for the Complete Beginner

Chapter 11 Manipulating Numbers

11.1 Introduction

Just like every high-level programming/scripting language, PHP provides many ready-to-use subprograms (functions) that you can use whenever and wherever you wish.

A “subprogram” is simply a group of statements packaged as a single unit. Each subprogram has a descriptive name and performs a specific task.

In PHP subprograms are called “functions”.

To better understand PHP's functions, let's take Heron's^[11] iterative formula that calculates the square root of a positive number.

where

►y is the ...

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PHP and Algorithmic Thinking for the Complete Beginner

by Aristides Bouras