Day 15: Object Oriented Programming in PHP
Introduction to OOPS
Php5 released in 2004 with OOP features like in C# and java. It was the big change in PHP and now we can code with classes and objects in PHP.
In next few days, I will guide you how to work with OOP in PHP.
let’s take a look terms related to Object Oriented Programming :
Class: is a collection of member variables and functions.
Object: is a instance of class, we can create multiple instance of a class.
Member Variable: variable defined in class are called member variable of that class. Variable holds data that will be invisible to the outside of the class.
Member Function: function defined in class are called member function and use to access data.
Inheritance: Inheritance is a mechanism wherein a new class is derived from an existing class.
Polymorphism: when same function used for different purpose it’s called Polymorphism. Like:- function name will remain same name but it take different number of arguments and can do different tasks.
Data Abstraction:Data abstraction represent to, providing only essential information to the outside world and hiding their background details.
Encapsulation: Encapsulation is the process of packing of data and functions into a single component.
Constructor: is a special type of function which will be called automatically whenever there is an object formation of a class.
Destructors: is a special type of function which will be called automatically whenever an object is deleted.
Program 42: Defining class and function in PHP
class myClass {
function display() {
echo “i am in display”;
}
}
$obj = new myClass();
$obj->display();
?>
Explanation: new is the keyword in above code. new keyword is use to create object of the class. $obj-> is used to call the function of the class.
Program 43: Constructor function
class myClass {
function __construct(){
echo “i am in constructor.”;
}
}
$obj = new myClass();
?>
As defined above Constructor is a special type of function which will be called automatically whenever there is an object formation of a class. Like in above example, we have created object of the class and constructor called automatically.
Program 44: Destructor function
class myClass {
function __destruct(){
echo “i am in destructor.”;
}
}
$obj = new myClass();
?>
As a constructor function we can also define a destructor function using function __destruct(). We can release all the resources with-in a destructor.
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