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

To suppress errors and bugs in a badly written code.

To handle an external error which the program cannot or is not meant to handle, like losing the database connection.


To use instead of `if…else` statements when you try to impress your boss and colleagues with your object oriented programming skills.


**(Fill in the blank)** What is exception handling used for?


(Fill in the blank) What is exception handling used for?

```
<?php
function divide($dividend, $divisor) {
 if($divisor == 0) {
 throw Exception("Division by 0 is not possible");
 }
 else{
 return dividend/divisor;
 }
}

try {
 echo divide(4, 0);
}
catch(Exception $e) {
 echo $e->getMessage();
}
?>
```
What is the output of the above code?

<pre><code>&lt;?php
function divide($dividend, $divisor) {
 if($divisor == 0) {
 throw Exception(&quot;Division by 0 is not possible&quot;);
 }
 else{
 return dividend/divisor;
 }
}

try {
 echo divide(4, 0);
}
catch(Exception $e) {
 echo $e-&gt;getMessage();
}
?&gt;
</code></pre>
What is the output of the above code?

What is the output of the following code?

```
<?php
function distanceTravel($speed, $time) {
 if($speed * $time < 0) {
 throw new Exception("Distance traveled cannot be negative");
 }
 else
 return "Distance traveled is " . ($speed * $time);
}

try {
 distanceTravel(100,5);
}
catch(Exception $e) {
 $e -> getMessage();
}
?>
```

What is the output of the following code?
<pre><code>&lt;?php
function distanceTravel($speed, $time) {
 if($speed * $time &lt; 0) {
 throw new Exception(&quot;Distance traveled cannot be negative&quot;);
 }
 else
 return &quot;Distance traveled is &quot; . ($speed * $time);
}

try {
 distanceTravel(100,5);
}
catch(Exception $e) {
 $e -&gt; getMessage();
}
?&gt;
</code></pre>

What is the output of the following code?
```
<?php
 try {
 $msg = 'Message 1';
 throw new Exception($msg);
 
 echo 'Message 2' . "\n";
 }
 catch (Exception $e) {
 echo $e->getMessage(), "\n";
 }
 
 echo 'Message 3';
?>
```

What is the output of the following code?
<pre><code>&lt;?php
 try {
 $msg = 'Message 1';
 throw new Exception($msg);
 
 echo 'Message 2' . &quot;\n&quot;;
 }
 catch (Exception $e) {
 echo $e-&gt;getMessage(), &quot;\n&quot;;
 }
 
 echo 'Message 3';
?&gt;
</code></pre>

What is the output of the following code?

```
<?php
function calculateCGPA($gradePoints,$creditValue) {
 if($gradePoints / $creditValue > 4) {
 throw new Exception("This is impossible");
 }
 else
 echo "Your CGPA is " . ($gradePoints / $creditValue);
 return true;
}

try {
 calculateCGPA(60,10);
}
catch(Exception $e) {
 echo 'Message: ' .$e -> getMessage();
}
?>
```

What is the output of the following code?
<pre><code>&lt;?php
function calculateCGPA($gradePoints,$creditValue) {
 if($gradePoints / $creditValue &gt; 4) {
 throw new Exception(&quot;This is impossible&quot;);
 }
 else
 echo &quot;Your CGPA is &quot; . ($gradePoints / $creditValue);
 return true;
}

try {
 calculateCGPA(60,10);
}
catch(Exception $e) {
 echo 'Message: ' .$e -&gt; getMessage();
}
?&gt;
</code></pre>

`Hey! I am eating apples.`

`Oh no, the  apple is rotten.`


```
<?php
echo "Hey! I am eating apples." . "\n";
try {
 $exception = "Oh no, the apple is rotten.";
 throw new Exception($Exception);
} catch(Exception $e) {
 echo $e->getMessage() . "\n";
}
?>
```
What is the output of the code above?

<pre><code>&lt;?php
echo &quot;Hey! I am eating apples.&quot; . &quot;\n&quot;;
try {
 $exception = &quot;Oh no, the apple is rotten.&quot;;
 throw new Exception($Exception);
} catch(Exception $e) {
 echo $e-&gt;getMessage() . &quot;\n&quot;;
}
?&gt;
</code></pre>
What is the output of the code above?

Test your understanding of exception handling.


Quiz: Exception Handling

Test your understanding of exception handling.

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: Exception Handling