What are the Object Oriented Programming Principles

What are the Object Oriented Programming Principles

Object Oriented Programming Principles – The principles of object oriented programming are three. These three principles are as follows-

What are three principles of object oriented programming

1. Encapsulation

What is Encapsulation

The combining of data and methods in a single unit is called encapsulation. This single unit is called class.

Data declared inside a class is not accessible directly from outside of the class.

Methods or functions declared inside the class can only access the data members declared in the class.

Encapsulation provides data hiding and prevents accidental use of data from outside of the class.

Example

Class Person

Data members are as follows-

1. Person name
2. Person id
3. Person address

Methods are as follows-

1. getdata()
2. showdata()

 

Data members person name, person id and person address can be used and manipulated by the methods getdata() and showdata() only.

Wrapping these data members and methods in a class is called encapsulation.

 

2. Inheritance

Inheritance is another principle of object oriented programming. It is a very important feature of object oriented programming that provides reusability in addition to better structuring of classes.

 

What is Inheritance

The mechanism of deriving a new class from an old class is called inheritance. The old class is called a superclass or parent class or base class.

The new class is called subclass or child class or derived class. Inheritance allows adding new features also in the child class and the features of parent class automatically accessed by the child class.

 

Kinds of Inheritance

 

 

 

There are following kinds of Inheritance-

• Single Level Inheritance

Once superclass and one subclass

 

• Multilevel Inheritance

In multilevel Inheritance new class is derived from another derived class

 

• Multiple Inheritance

Under multiple Inheritance new class is derived from two or more classes.

 

• Hierarchical Inheritance

One class may have two or more derived classes

 

• Hybrid Inheritance

Combination of two or more types of inheritance is called hybrid Inheritance

 

3. Polymorphism

What is Polymorphism

Polymorphism means one name and multiple forms.

One function or method behaves differently in different situations.

According to the parameters and class, one method or function works differently.

There are various kinds of polymorphism.

• Compile time polymorphism

Compile time polymorphism further divided into two categories 1. Method overloading 2. Operator overloading

• Run time polymorphism

Run time polymorphism is implemented via virtual functions or overriding methods.

 

 

What are the 4 principles of object oriented programming

Besides above mentioned three principles of object oriented programming one more principle is also considered that is Abstraction.

 

 

Therefore four principles of object oriented programming are the following-

1. Encapsulation
2. Inheritance
3. Polymorphism
4. Abstraction

 

Abstraction

What is Abstraction

Abstraction means the act of representing essential features without including the background information. Classes use the concept of abstraction.

Classes defined as a list of abstract attributes such as roll number, first name, second name, age, address, etc. and functions or methods that operate on these attributes.

Class encapsulates all the essential properties of the objects.

 

What are the 4 pillars of OOP

Four pillars of abstraction of oops are

1. Encapsulation
2. Inheritance
3. Polymorphism
4. Abstraction

 

Therefore, Object Oriented Programming Principles are three Encapsulation, Inheritance, and Polymorphism, but sometimes Abstraction is also considered the fourth principle of object oriented programming.

– Object Oriented Programming Principles