OOPS CONCEPT IN PHP PDF
Classes are the blueprints for php objects - more on that later. One of the big differences between functions and classes is that a class contains both data. performed in PHP. PHP has traditionally not been an object-oriented programming objects and classes were introduced into PHP 3 in In , PHP 4. You will learn PHP Built-in Function, Predefined Variables Examples, Object Same way there is object oriented programming concepts which assume.
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PHP is an object oriented scripting language. The three basic principles of OOP are Encapsulation, Inheritance, Polymorphism. PHP Advanced and Object-Oriented Programming. Larry Ullman . Advanced Database Concepts. .. uses objects instead of procedural code. Of course, all of. (Chapter 6). 1. Topics: OOP concepts – overview, throughout the chapter; Defining and using objects Advanced object-oriented functionality in PHP. Comparing . ppti.info~frank/csc/Examples/PHP_OO/ ppti.info
Now we have learned about inheritance and their different types.
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Object Oriented Programming : Encapsulation Encapsulation is a mechanism where you bind your data and code together as a single unit. It also means to hide your data in order to make it safe from any modification.
What does this mean? The best way to understand encapsulation is to look at the example of a medical capsule, where the drug is always safe inside the capsule. Similarly, through encapsulation the methods and variables of a class are well hidden and safe. We can achieve encapsulation in Java by: Declaring the variables of a class as private. Providing public setter and getter methods to modify and view the variables values. We have then created a getter and setter methods through which we can get and set the name of an employee.
Through these methods, any class which wishes to access the name variable has to do it using these getter and setter methods. Object Oriented Programming : Abstraction Abstraction refers to the quality of dealing with ideas rather than events. It basically deals with hiding the details and showing the essential things to the user.
If you look at the image here, whenever we get a call, we get an option to either pick it up or just reject it. But in reality, there is a lot of code that runs in the background. Therefore, abstraction helps to reduce complexity. Now what does the abstract keyword mean?
If a class is declared abstract, it cannot be instantiated, which means you cannot create an object of an abstract class. Also, an abstract class can contain abstract as well as concrete methods.
In an interface, each method is public and abstract but it does not contain any constructor. So an interface basically is a group of related methods with empty bodies.
But their working is going to be different. Therefore, not all my subclasses have the same logic written for change gear.
But suppose, someone else is driving a super car, where it increment by 30kms or 50kms. Again the logic varies. Similarly for applybrakes, where one person may have powerful brakes, other may not.
After that, I will create a child class which implements this interface, where the definition to all these method varies.
SpeedUp ; A6. Implementing an interface allows a class to become more formal about the behavior it promises to provide.
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So I hope you guys are clear with the interface and how you can achieve abstraction using it. Finally, the last Object oriented programming concept is Polymorphism.
It is the ability of a variable, function or object to take on multiple forms. In other words, polymorphism allows you define one interface or method and have multiple implementations. You can think of a class as a template for making many instances of the same kind or class of object.
You define a class once and then make many objects that belong to it. Objects are also known as instance.
This data will be invisible to the outside of the class and can be accessed via member functions. These variables are called attribute of the object once an object is created. Here child class will inherit all or few member functions and variables of a parent class.
OOPS Concept Definitions
This is also called a base class or super class. This is also called a subclass or derived class. For example function name will remain same but it take different number of arguments and can do different task. Similarly functions can also be overloaded with different implementation.
Function definitions look much like standalone PHP functions but are local to the class and will be used to set and access object data. Once you defined your class, then you can create as many objects as you like of that class type.
PHP Object Oriented Programming (OOPs) concept Tutorial with Example
Following is an example of how to create object using new operator. Here we have created three objects and these objects are independent of each other and they will have their existence separately.
Next we will see how to access member function and process member variables. After creating your objects, you will be able to call member functions related to that object. One member function will be able to process member variable of related object only. Following example shows how to set title and prices for the three books by calling member functions. Constructor Functions are special type of functions which are called automatically whenever an object is created.
So we take full advantage of this behaviour, by initializing many things through constructor functions. You can pass as many as arguments you like into the constructor function.
Following example will create one constructor for Books class and it will initialize price and title for the book at the time of object creation. Now we don't need to call set function separately to set price and title.
PHP Class Object
We can initialize these two member variables at the time of object creation only. You can release all the resources with-in a destructor.
PHP class definitions can optionally inherit from a parent class definition by using the extends clause.
Automatically has all the same member functions as the parent, which by default will work the same way as those functions do in the parent. Function definitions in child classes override definitions with the same name in parent classes.
In a child class, we can modify the definition of a function inherited from parent class.
Unless you specify otherwise, properties and methods of a class are public. Till now we have seen all members as public members. If you wish to limit the accessibility of the members of a class then you define class members as private or protected. By designating a member private, you limit its accessibility to the class in which it is declared.Objects are often very similar.
It is simply "One thing, can use in different forms". It is created many times as you required.
Note: All the remaining classes which are not abstract are called Concrete Classes Q:- What is the need of abstract class? We can approach the methods similar to the way that we approach the properties, but we first need to create at least one object from the class.
Following is an example of how to create object using new operator. Blockchain Go Programming Reviews. We can achieve encapsulation in Java by: Declaring the variables of a class as private.