Top 25 PHP OOPS Interview Questions

Are you looking for a job for an Object-Oriented Programming (OOP) in PHP and looking for Top PHP OOPS Interview Questions?

If yes, you are at the perfect spot for getting good PHP OOPS Interview Questions and topics that can help you to get your dream job. (OOPS) Object-Oriented Programming in PHP is a programming process to divide like tasks into Class and Object to generate reusable code.

As we can imagine something as various parts like a Computer made of different things like the processor, ram, motherboard, hard disk, smps, monitor etc. There are many jobs for Object-Oriented Programming with PHP open in reputed organisations for many positions like.

  • Software Developer
  • System Engineer, Software Development Engineer
  • Lecturer
  • Application Developer etc.

Commonly asked PHP OOPS Interview Questions

1) What Is Object-Oriented Programming?

  • Object-oriented programming system (OOPs) is a programming language model organised around objects.
  • Objects are instances of classes, which are used to interact with one another.
  • An application can be of any type like it can be a web-based application, windows based application etc. In object-oriented programming, everything revolves around the objects and class.
  • OOPS is shortened as Object-Oriented Programming system in which programs are regarded as a collection of states.

2) Explain basic concepts of OOPS?

Concepts of OOPS:

  • Abstraction
  • Encapsulation
  • Inheritance
  • Polymorphism

3) What Are Properties Of Object-Oriented Systems?

  • Inheritance
  • Data Encapsulation
  • Extensible data types and classes
  • Support for complex data types
  • Aggregation
  • Association

4) What is a class?

  • A class is simply a type of object. It is the plan or template that describes the details of an object.

5) What is the Object?

  • An object is an instance of a class, It has its own behaviour, state behaviour, and connections.

6) What is an Encapsulation?

  • Encapsulation is a part of an object, and it describes all data. That hidden data are restricted to the members of that class.
  • Class are Public, Private, Protected, Internal and Protected Internal.

7) What is Polymorphism?

  • Polymorphism is nothing but assigning behaviour or value in a subclass to something that was already declared in the main class. Simply, polymorphism takes more than one form.

8) What is Inheritance?

  • Inheritance is a concept where one class assigns the formation and behaviour defined in another class. If Inheritance is applied to one class is called Single Inheritance, and if it depends on multiple classes, it is called multiple Inheritance.

9) What are manipulators?

  • Manipulators are the purposes which can be used in combination with the insertion (<<) and extraction (>>) operators on an object. Examples are endl and setw.

10) What Is the Difference Between Class And Interface?

  • Interfaces don’t include business logic.
  • You must extend the interface to use.
  • A class can be instantiated by making its objects. An interface is not be instantiated as the methods declared inside an interface are abstract and does not perform any action.
  • You can’t create an object of the interface.
  • A class is declared using a keyword ‘class’. An interface is created using a keyword ‘interface’.
  • The members of a class can have access specifier like public, private, protected. The members of an interface are public as they have to be accessed by the classes implementing them.
  • The methods inside a class are assigned to act on the fields listed in the class. As interface requires in the declaration of fields, the processes inside an interface are purely abstract.

11) What is Interface in PHP?

  • Interfaces are assigned using the interface keyword.
  • All methods are declared in an interface that must be public. Classes defined as Interface is not be instantiated(create object).
  • You can inherit the number of interface class at the time of extending and number of abstract class separated by a (,)comma.
  • All methods must be implemented within a child class, failure to do so will result in a fatal error.
  • To extend the interface class, the implements operator is used.
  • The extends operator is used.
  • A number of the parameter must match.

12) What is Overloading?

  • It is a dynamically created method/resources and performed by magic methods. Overloading method/resources are invoked when interacting with properties or methods that have not been published or are not visible in the current field, Means we you are calling a function which does not exist.

13) What is function overloading?

  • Function overloading is a normal function, but it can perform several tasks. It allows creating several methods with the same name which differ from others by the type of both input and output of the function.

14) What is Operator Overloading?

  • A function where several operators are applied and based on the arguments is called Operator Overloading. Operator -,* can be used to pass by the function, and it has its own precedence to execute.

15) What is static and dynamic Binding?

  • Binding is the name with the class.
  • Static Binding is binding in that name can be associated with the class and it is also called as early binding.
  • Dynamic Binding is binding in name can be associated with the class during execution time, and it is called as Late Binding also.

16) How many instances are created for an abstract class?

  • Zero Instances will be made for an abstract class. In other Words, you can’t create an instance of an Abstract Class.

17) Which keyword can be used for overloading?

  • Operator keyword is used for overloading.

18) What differs the Class and the Object?

  • An object is derived from the class. The objects can hold multiple information, but classes don’t have any details. Definition of functions and properties can be done in class and can be used by the object.
  • The class have sub-classes, while an object doesn’t have sub-objects.

19) What is an abstraction?

  • Abstraction is an essential feature of OOPS, and it explains the necessary details to the client of an object. It shows only needed details for an object, not the internal constructors, of an object. When you want to turn on the television, it is not mandatory to know the internal circuitry needed to turn on the TV. Whatever is required to turn on TV will be described by using an abstract class.

20) What are the access modifiers?

  • Access modifiers describe the scope of the method and variables that can be accessed from other different objects or classes. Five types of access modifiers and they are as below:
    • Private
    • Public
    • Protected
    • Friend
    • Protected Friend

21) What Is Scope Resolution Operator?

  • The Scope Resolution Operator is a double colon (::) that allows a way to static, constant, and overridden properties or methods of a class.

Following are different uses Access to static

  1. Access the constant.
  2. Access the methods of a parent class.
  3. Access the overridden properties of the parent class.

22) What are the various types of constructors?

There are three types of constructors:

  • Default Constructor:- With no parameters.
  • Parametric Constructor:- Create a new instance of a class and also passing arguments simultaneously with Parameters.
  • Copy Constructor:-Which forms a new object as a copy of an existing object.

23) What are Traits In Php?

  • Traits are a circuitry for code reuse in single inheritance.
  • A Trait is similar to a class, but only intended to group functionality in a fine-grained and consistent way.
  • It is impossible to instantiate a Trait but in addition to common inheritance. It is assigned to reduce some limitations of single inheritance to reuse sets of methods freely in several independent classes living in several class hierarchy.

24) What Is UML?

  • UML stands for Unified Modeling Language.

Following things with UML:

  1. Execute project complexity.
  2. Build the database schema.
  3. Design reports.

25) What are the advantages of object-oriented programming?

  • Code Reusability: Used to achieve through inheritance and traits.
  • Modularity: Used to achieve by breaking large code into small modules, Modularity reduces complexity.
  • Maintainability: Used to maintain code which follows Object-Oriented Programming Concepts.
  • Testability: it is easy to test.
  • Security: Used to achieve by Encapsulation
  • Flexibility: We can make by polymorphism.
  • Testability: it is easy to test.

These are commonly asked Top 25 PHP OOPS Interview Questions.

Also read: Top 25 SQL Queries Interview Questions

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