Introduction to PHP OOP Interview Questions and Answers
PHP (Hypertext Pre-processor) is a server-side scripting language used in web development which is based on Object-Oriented programming (OOP) language. It was designed primarily based on C++ programming language. It is also used a general-purpose programming language. It was originally developed by Rasmus Lerdorf in the year 1994. This PHP code can be embedded into HTML code in the web development.
PHP is a dynamically typed programming language which supports different Operating Systems such as Windows, Unix etc. PHP standards, specifications, and implementations are provided by The PHP group. PHP stands for Personal Home Page.
Now, if you are looking for a job which is related to PHP OOP then you need to prepare for the PHP OOP Interview Questions. It is true that every interview is different as per the different job profiles but still to clear the interview you need to have a good and clear knowledge of PHP OOP. Here, we have prepared the important PHP OOP Interview Questions and Answers which will help you get success in your interview.
Below are the 10 important PHP OOP Interview Questions and Answers that are frequently asked in an interview. these questions are divided into two parts are as follows:
Part 1 – PHP OOP Interview Questions (Basic)
This first part covers basic PHP OOP Interview Questions and Answers
1. What is a session in PHP?
A session in a PHP is used to store the information or data across multiple web pages on a web browser which is not stored on the local computer’s memory. A session in PHP is started using the function session_start() and the session variables can be set using the global variable called $_SESSION. In the process of creating or starting a session in PHP, the ideal scenario will be a unique identifier will be created during the start of a session, then a cookie will be sent to the user’s machine to identify the unique session and this unique id is stored in the remote server being called to identify the user during the life cycle of that session. Once the session is timed out, then the entire user session data will be deleted. The default session timeout period is 24 minutes in PHP.
2. What are constructor and destructor in PHP?
This is the basic PHP OOP Interview Questions which is asked in an interview. The Constructor in a PHP is used to create an object of its class type which is used to initialize the properties of the object using a method called _construct(). The constructor in PHP can be overloaded by passing the different arguments by calling the same method with the different number of arguments inside the same class declaration. The Destructor in a PHP is used to call when the lifecycle of the object is going to be ended to release the memory occupied by it or to garbage collect the same. The destructor can be called using the method _destrcut().
3. What are the general uses of PHP?
The general uses of PHP are – It can perform system function operations such as create, read, open, close and write them to and from the computer memory. It can access cookies variables and set the values in the browser. It can also provide a restriction to access some web pages that provide security. The data can also be encrypted using PHP.
Let us move to the next PHP OOP Interview Questions And Answer.
4. What is an Interface in PHP?
An interface is a contract to provide the implementation of different functions as per the user’s requirement. This can also be called as the blueprint of the required structure. An interface can be used and implemented many ways inside the implementation class.
5. What are the different data types in PHP?
The different data types in PHP are String, Floating point numbers such as double, Integer, Boolean, Array, Object, NULL, and Resource. A PHP String is an array of characters. An integer is a number without decimal points. A Boolean can be true or false. An Object is a type which can be explicitly declared to store different types of data in it by encapsulating it. An array is an identical list of data types stored in a sequence which can be accessed based on an index. A NULL value is also a data type which indicates no value and having a single value NULL.
Part 2 –PHP OOP Interview Questions (Advanced)
Let us now have a look at the advanced PHP OOP Interview Questions.
6. What is OOP and how PHP is an object-oriented language?
An Object-Oriented programming (OOP) language will have object-oriented features such as Abstraction, Encapsulation, Inheritance, polymorphism etc., PHP was primarily based on C++ programming language which is an object-oriented programming language. A PHP class contains properties and methods which are used to create an object of that class and each object will have its own properties and values.
7. What is a Namespace in PHP?
A Namespace in PHP is used to encapsulate the items which are similar to that of abstraction in Object Oriented programming concepts. Namespaces are used to establish a relationship among classes, functions, and constants. A Namespace can be defined using the keyword The namespace keyword is reserved in PHP for its internal use to avoid conflict with the user created identifiers.
Let us move to the next PHP OOP Interview Questions And Answer.
8. What is a final keyword in PHP and when it is used?
The final keyword in PHP is used to mark either a class or a function as final. If a class is marked as final, it cannot be extended to use its properties or methods. It prevents its child classes from overriding a method. If only a function is marked as final, then it can’t be extended. The final keyword was introduced in PHP 5 version. A final declaration can be done by prefixing the class name or function name with the final keyword.
9. What is echo and print in PHP?
The echo and print are two basic ways of getting output in PHP. The functionality of echo and print are identical in PHP to get the output. The differences between echo and print are: echo doesn’t return any value whereas print returns a value of 1 which can be used in expressions. Echo takes multiple arguments whereas print takes a single argument. Echo can be used by calling echo or echo() whereas print can be called by using a print keyword.
10. What is require and include in PHP?
This is the advanced PHP OOP Interview Questions which is asked in an interview. The require and include statements in PHP are available from PHP 4 and above versions which are identical with some difference. Include statement includes the specified file and evaluates it whereas the requirement is also having the same feature but it produces a fatal error upon failure with an error E_COMPILE_ERROR level error which is a compilation error. In this case, it stops the execution of the script and halts the run-time flow. The files will be included based on the file path given in the script.
This has been a guide to List Of PHP OOP Interview Questions and Answers so that the candidate can crackdown these PHP OOP Interview Questions easily. Here in this post, we have studied about top PHP OOP Interview Questions which are often asked in interviews. You may also look at the following articles to learn more –
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