PHP Variables
PHP Data Types
PHP Echo & Print
PHP Strings
PHP Numbers
PHP Constants
PHP Operators
PHP if...else...elseif Statements
Switch Statement
PHP Loops
PHP Arrays
Superglobals
PHP Coding Standards
PHP Form Handling
PHP Form Validation
PHP URLs Validation
PHP Form Required Validation
Complete Form Example
PHP File Functions Open/Read
PHP File Create/Write
PHP File Upload
PHP Cookies Handling
PHP Session Handling
PHP filter_var() Function
PHP Validation Filters
PHP Sanitization Filters
Using Filters
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JSON
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MySQL Database
MySQL Connect
MySQL Commands-Creating a Table
MySQL Commands-Inserting The data
MySQL Commands-Prepared Statement
MySQL Commands-Selecting The Data
MySQL Commands-Where and Order By
MySQL Commands-Deleting And Updating The Data
PHP-OOP Introduction
PHP-Classes/Objects
PHP-Constructor/Destructor
PHP-Access Modifiers
PHP-Inheritance
PHP-Inheritance and Protected Access Modifier
PHP-Overriding Inherited Methods
PHP-Final keyword
PHP-Abstract Classes
PHP-Constants
PHP-Traits
PHP-Static Methods and Properties
Introduction to Functions
Defining A function
Returning Values From A Function
Dynamic Function Calls
Variable Scope
Understanding Arguments Or Parameters
Testing For A Function Existence
Returning Multiple Values From A Function
Making practical Use By Building Code Libraries For Code Re-usability
Using Include() And Require()
Abstract classes in PHP is a class that cannot be instantiated i.e. you cannot create an object for the abstract class. Abstract class can have both abstract methods and non- abstract methods but at least one method should be abstract in an abstract class. You can declare abstract classes and methods using abstract keyword. Abstract methods are not implemented in the base class and are just declared. The implementation is done in the child class of this abstract base class.
Syntax:
abstract class class_name
{
abstract public function function1();
public function function2();
}
For example:
abstract class Fruit{
abstract function message();
}
class Apple extends Fruit {
function message() {
echo “ An apple a day keeps a doctor away”;
}
}
$Apple = new Fruit(); // It will give error because Fruit is abstract class
$Apple = new Apple();
$Apple -> message();
?>
You can also create a constructor for the abstract class like other programming languages. When a child class is inherited using abstract class the name of the abstract method should be same in the derived class. The number of parameters should also be same as in the abstract method and additional parameters can also be added in the derived class methods.
If you try to implement the abstract method in the abstract class it will display and error message at runtime. So, you need a child class to implement the methods of an abstract class.
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