OOP is a methodology or paradigm that provides many concepts. The basic concepts of Object Oriented Programming are given below:
Classes and Objects: Classes are used to specify the structure of the data. They define datatype. You can create any number of objects from a class. Objects are the instances of classes.
Encapsulation: Encapsulation is a mechanism which binds the data and associated operations together and thus hide the data from outside world. Encapsulation is also known as data hiding. In C++, It is achieved using the access specifiers i.e. public, private and protected .
Abstraction: Abstraction is used to hide the internal implementations and show only the necessary details to the outer world. Data abstraction is implemented using interfaces and abstract classes in C++.
Some people confused about Encapsulation and abstraction. But they both are different.
Inheritance: Inheritance is used to inherit the property of one class into another class. It facilitates you to define one class in term of another class.   _{Your Comment}