Gain insights into object-oriented programming in PHP. Discover classes, objects, methods, inheritance, and more. Build dynamic server-side applications using OOP techniques and PHP database management.

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Object-oriented programming is perhaps the dominant development paradigm for leading languages including Java, C#, and Python. The rich class and inheritance framework wasn’t fully implemented in modern PHP until 2015, and best practices for object-oriented programming are still emerging.

This course is an introduction to object-oriented programming in PHP. You’ll start with the basics of the OOP paradigm and get familiar with classes, objects, methods, and properties. You’ll then chain methods and properties using the this keyword before working with access modifiers and magic methods. With these basics down, you’ll take a deep dive into object-oriented programming in PHP, including inheritance, abstraction, polymorphism, and namespaces. After exploring exception handling, you’ll use these object-oriented techniques to build, manage, and edit a PHP database.

By the end of this course, you’ll be prepared to build dynamic server-side applications using object-oriented programming in PHP.

Object-Oriented Programming in PHP

Whenever we want to use a class’s method without instantiating an object of that class.


For utilities such as conversion between units of measurements, sanitation, encryption, and so on.


When we would like to unit test our code.

When are static methods and properties appropriate?


When are static methods and properties appropriate?

Which keyword is used to define a trait?


Which keyword is used to define a trait?

Which types can be found within a trait?


Which types can be found within a trait?

**(True or False)** It is appropriate to use traits in a scenario in which all of the child classes of an interface need the same methods.


(True or False) It is appropriate to use traits in a scenario in which all of the child classes of an interface need the same methods.

`The number of times the game was played is 0`

`The number of times the game was played is 4`

`The number of times the game was played is 0`

`The number of times the game was played is 1`

`The number of times the game was played is 0`

`The number of times the game was played is 2`

`The number of times the game was played is 0`

`The number of times the game was played is 0`

What is the output of the following code?

```
<?php
class GamePlay{

 static public $attempts = 0;

 static public function play(){
 self::$attempts = self::$attempts * self::$attempts;
 }

 static public function increaseAttempts($int){
 $int = (int)$int;
 self::$attempts += $int;
 }
}
 
echo GamePlay::play();
echo "The number of times the game was played is " . GamePlay::$attempts . "\n";
GamePlay::increaseAttempts(2);
echo GamePlay::play();
echo "The number of times the game was played is " . GamePlay::$attempts;
?>
```

What is the output of the following code?
<pre><code>&lt;?php
class GamePlay{

 static public $attempts = 0;

 static public function play(){
 self::$attempts = self::$attempts * self::$attempts;
 }

 static public function increaseAttempts($int){
 $int = (int)$int;
 self::$attempts += $int;
 }
}
 
echo GamePlay::play();
echo &quot;The number of times the game was played is &quot; . GamePlay::$attempts . &quot;\n&quot;;
GamePlay::increaseAttempts(2);
echo GamePlay::play();
echo &quot;The number of times the game was played is &quot; . GamePlay::$attempts;
?&gt;
</code></pre>

What is the output of the following code?

```
<?php
class Intro
{
 static private function sayHello()
 {
 return "Hello! Have a blessed day.";
 }
}
Intro::sayHello();
?>
```

What is the output of the following code?
<pre><code>&lt;?php
class Intro
{
 static private function sayHello()
 {
 return &quot;Hello! Have a blessed day.&quot;;
 }
}
Intro::sayHello();
?&gt;
</code></pre>

`Fatal error: static method should always be public`


We cannot inherit static properties or methods.


What is the output of the following code?

```
<?php
class Car
{
 static protected function sayHello()
 {
 echo "Hello! I am a car. ";
 }
}

class Bmw extends Car
{
 static public function sayHello()
 {
 parent::sayHello();
 echo "My name is BMW.";
 }
}
Bmw::sayHello();
?>
```

What is the output of the following code?
<pre><code>&lt;?php
class Car
{
 static protected function sayHello()
 {
 echo &quot;Hello! I am a car. &quot;;
 }
}

class Bmw extends Car
{
 static public function sayHello()
 {
 parent::sayHello();
 echo &quot;My name is BMW.&quot;;
 }
}
Bmw::sayHello();
?&gt;
</code></pre>

Introduction

Classes and Objects

Using the $this Keyword for Chaining Methods and Properties

Access Modifiers

Magic Methods and Constants Unveiled

Inheritance in Object-oriented Programming

Abstract Classes and Interfaces

Polymorphism and Type Hinting

Static Methods & Properties and Traits

Namespaces & Dependency Injection

Exception Handling

PHP Database

Model-view-controller (MVC)

Conclusion

Appendix

Quiz: Static Methods & Properties and Traits