OOPS -Concepts in PHPCall US : 011-65164822Add:- Block C 9/8, Sector-7, Rohini, Delhi -110085www.cpd-india.comwww.blog.cpd-india.comCPD TECHNOLOGIES

Topics to be coveredWhat is OOPSClass & ObjectsModifierConstructor DeconstructorClass ConstantsInheritance In PhpMagic FunctionPolymorphismInterfacesAbstract ClassesStatic Methods And PropertiesAccessor MethodsDetermining A Object's Class

What Is Oop ?Object Oriented Programming (OOP) is the programming method that involves the use of the data , structure and organize classes of an application. The data structure becomes an objects that includes both functions and data. A relationship between one object and other object is created by the programmerwww.cpd-india.com

ClassesA class is a programmer defined datatype which include local fuctions as well as local data.Like a pattern or a blueprint a oopsclasshas exact specifications. The specification is the class' s contract.

An object is a like a container that contains methods and properties which are require to make a certain data types useful. An objects methods are what it can do and its properties are what it knows.Object

Modifier

ModifierIn object oriented programming, some Keywords are private and some are public in class. These keyword are known as modifier. These keywords help you to define how these variables and properties will be accessed by the user of this class. www.cpd-india.com

ModifierPrivate: Properties or methods declared as private are not allowed to be called from outside the class. However any method inside the same class can access them without a problem. In our Emailer class we have all these properties declared as private, so if we execute the following code we will find an error. www.cpd-india.com

Modifier The above code upon execution gives a fatal error as shown below:

Faprivate property emailer::$subject in C:\OOP with PHP5\Codes\ch1\class.emailer.php on line 43tal error: Cannot access That means you can't access www.cpd-india.com

ModifierPublic: Any property or method which is not explicitly declared as private or protected is a public method. You can access a public method from inside or outside the class. Protected: This is another modifier which has a special meaning in OOP. If any property or method is declared as protected, you can only access the method from its subclass. To see how a protected method or property actually works, we'll use the following example:

ModifierTo start, let's open class.emailer.php file (the Emailer class) and change the declaration of the $sender variable. Make it as follows:

protected $sender

Now create another file name class.extendedemailer.php with the following code: www.cpd-india.com

Modifier

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Constructor & DestructorConstructor is Acclimated to Initialize the Object.Arguments can be taken by constructor.A class name has same name as Constructor.Memory allocation is done by Constructor.www.cpd-india.com

Constructor & DestructorThe objects that are created in memory, are destroyed by the destructor.Arguments can be taken by the destructor.Overloading is possible in destructor.It has same name as class name with tiled operator.

ClassContants

Class ConstantsYou can make constants in your PHP scripts utilizing the predefine keyword to define (constant name, constant value). At the same time to make constants in the class you need to utilize the const keyword. These constants really work like static variables, the main distinction is that they are read-only.www.cpd-india.com

Class Constants

Class Constants} public function count($order) { if ($order==self::ASC) asort($this->words); else if($order==self::DESC) arsort($this->words);

foreach ($this->words as $key=>$val) echo $key ." = ". $val.""; }}?>www.cpd-india.com

Inheritance

Inheritance In PhpInheritance is a well-known programming rule, and PHP makes utilization of this standard in its object model. This standard will influence the way numerous objects and classes identify with each other. For illustration, when you extend a class, the subclass inherits each public and protected method from the guardian class. Unless a class overrides those techniques, they will hold their unique functionality

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Inheritance

Magic Functions

Magic FunctionsThere are some predefine function names which you cant use in your programme unless you have magic functionality relate with them. These functions are known as Magic Functions. Magic functions have special names which begine with two underscores.www.cpd-india.com

Magic Functions_ _construct()_ _deconstruct()_ _call()_ _callStatic()_ _get()_ _set()_ _isset()_ _unset()__sleep()__wakeup()__tostring()__invoke()__set_state()__clone()__debugInfo()

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Magic Functions_ _construct() Construct function is called when object is instantiated. Generally it is used in php 5 for creating constructor

_ _deconstruct()It is the opposite of construct function. When object of a class is unset, this function is called.www.cpd-india.com

Magic Functions_ _call()When a class in a function is try to call an accessible or inaccessible function , this method is called.

_ _callStatic()It is similar to __callStatic() with only one difference that is its triggered when you try to call an accessible or inaccessible function in static context.

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Magic Functions_ _get()This function is triggered when your object try call a variable of a class which is either unavailable or inaccessible.

_ _set()This function is called when we try to change to value of a property which is unavailable or inaccessible.www.cpd-india.com

Polymorphismwww.cpd-india.com

PolymorphismThe ability of a object, variable or function to appear in many form is known as polymorphism. It allows a developer to programme in general rather than programme in specific. There are two types of polymorphism.compile time polymorphismrun-time polymorphism".www.cpd-india.com

Interfaces

InterfacesThere are some specific set of variable and functions which can be called outside a class itself. These are known as interfaces. Interfaces are declared using interface keyword.

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Abstract Classes

Abstract ClassesA class which is declared using abstract keyword is known as abstract class. An abstract class is not implemented just declared only (followed by semicolon without braces)

Static Method And Properties

Static Methods & PropertiesIn object oriented programming, static keyword is very crucial. Static properties and method acts as a significant element in design pattern and application design. To access any method or attribute in a class you must create an instance (i.e. using new keyword, like $object = new emailer()), otherwise you can't access them. But there is a difference for static methods and properties. You can access a static method or property directly without creating any instance of that class. A static member is like a global member for that class and all instances of that class

Static Methods & Properties

Static Methods & Properties{ //instantiate a new PostgreSQL Driver object and return } public static function getSQLiteDriver() { //instantiate a new MySQL Driver object and return }}?>www.cpd-india.com

Accessor Method

Accessor MethodAccessor methods are simply methods that are solely devoted to get and set the value of any class properties. It's a good practice to access class properties using accessor methods instead of directly setting or getting their value. Though accessor methods are the same as other methods, there are some conventions writing them. There are two types of accessor methods. One is called getter, whose purpose is returning value of any class property. The other is setter that sets a value into a class property. www.cpd-india.com

Accessor Method

Accessor Methodpublic function setRoll($roll){$this->roll =$roll;}public function getName(){return $this->name;}public function getRoll(){return $this->roll;}}?>www.cpd-india.com

Determining A Object's Classpublic function setRoll($roll){$this->roll =$roll;}public function getName(){return $this->name;}public function getRoll(){return $this->roll;}}?>www.cpd-india.com

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