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OOPS - concepts in php

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.

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OOPS - concepts in php

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  1. OOPS -Concepts in PHP Call US : 011-65164822 CPD TECHNOLOGIES Add:- Block C 9/8, Sector-7, Rohini, Delhi -110085 www.cpd-india.com www.blog.cpd-india.com

  2. What is OOPS Class & Objects Modifier Constructor Deconstructor Class Constants Inheritance In Php Magic Function Polymorphism Topics to be covered Interfaces Abstract Classes Static Methods And Properties Accessor Methods Determining A Object's Class

  3. 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 programmer What Is Oop ? www.cpd-india.com

  4. A class is a programmer defined datatype which include local fuctions as well as local data. Like a pattern or a blueprint a oops class has exact specifications.  The specification is the class' s contract. Classes

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

  6. Modifier

  7. In 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. Modifier www.cpd-india.com

  8. Private: 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. Modifier www.cpd-india.com

  9. <? include_once("class.emailer.php"); $emobject = new Emailer("hasin@somewherein.net"); $emobject->subject = "Hello world"; ?> Modifier • The above code upon execution gives a fatal error as shown below: • <b>Faprivate property emailer::$subject • in <b>C:\OOP with PHP5\Codes\ch1\class.emailer.php</b> on line • <b>43</><br /> • tal error</b>: Cannot access That means you can't access www.cpd-india.com

  10. Public: 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: Modifier

  11. To 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: Modifier www.cpd-india.com

  12. <? class ExtendedEmailer extends emailer { function __construct(){} public function setSender($sender) { $this->sender = $sender; } } ?> Modifier www.cpd-india.com

  13. Constructor 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. Constructor & Destructor www.cpd-india.com

  14. The 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. Constructor & Destructor

  15. ClassContants

  16. You 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. Class Constants www.cpd-india.com

  17. <? class WordCounter { const ASC=1; //you need not use $ sign before Constants const DESC=2; private $words; function __construct($filename) { $file_content = file_get_contents($filename); $this->words = (array_count_values(str_word_count(strtolower ($file_content),1))); Class Constants www.cpd-india.com

  18. } 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."<br/>"; } } ?> Class Constants www.cpd-india.com

  19. Inheritance

  20. Inheritance 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 Inheritance In Php www.cpd-india.com

  21. Inheritance

  22. Magic Functions

  23. There are some predefine function names which you can’t 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. Magic Functions www.cpd-india.com

  24. _ _construct() _ _deconstruct() _ _call() _ _callStatic() _ _get() _ _set() _ _isset() _ _unset() Magic Functions __sleep() __wakeup() __tostring() __invoke() __ set_state() __ clone() __ debugInfo() www.cpd-india.com

  25. _ _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. Magic Functions www.cpd-india.com

  26. _ _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. Magic Functions www.cpd-india.com

  27. _ _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. Magic Functions www.cpd-india.com

  28. Polymorphism www.cpd-india.com

  29. The 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 polymorphism run-time polymorphism". Polymorphism www.cpd-india.com

  30. Interfaces

  31. There 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. <? //interface.dbdriver.php interface DBDriver { public function connect(); public function execute($sql); } ?> Interfaces www.cpd-india.com

  32. Abstract Classes

  33. A 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) <? //abstract.reportgenerator.php abstract class ReportGenerator { public function generateReport($resultArray) { //write code to process the multidimensional result array and //generate HTML Report } } ? Abstract Classes www.cpd-india.com

  34. Static Method And Properties

  35. In 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

  36. <? //class.dbmanager.php class DBManager { public static function getMySQLDriver() { //instantiate a new MySQL Driver object and return } public static function getPostgreSQLDriver() Static Methods & Properties www.cpd-india.com

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

  38. Accessor Method

  39. Accessor 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. Accessor Method www.cpd-india.com

  40. <? class Student { private $name; private $roll; More free ebooks : http://fast-file.blogspot.com Chapter 2 [ 39 ] public function setName($name) { $this->name= $name; } Accessor Method www.cpd-india.com

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

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

  43. CPD TECHNOLOGIES Block C 9/8, Sector-7, Rohini, Delhi -110085 support@cpd-india.com

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