Object-Oriented Programming (OOP) is a programming paradigm that is based on the concept of "objects". Objects are instances of classes, which are essentially blueprints for creating objects. Classes contain data members (also called instance variables or attributes) and member functions (also called methods) that operate on that data.

OOPS in C++ is implemented through classes, objects, inheritance, polymorphism, and encapsulation.

• Classes: A class is a blueprint for creating objects. It defines the data members and member functions of an object. Classes allow for encapsulation, which means that the implementation details of a class can be hidden from the outside world, and only the public interface is visible.
• Objects: An object is an instance of a class. It contains its own set of data members and can access the member functions of its class. Objects are created using the class constructor, which is a special member function that is called automatically when an object is created.
• Inheritance: Inheritance is a mechanism that allows a new class to be created from an existing class. The new class, called the derived class, inherits all the data members and member functions of the base class. Inheritance allows for code reuse and helps to promote the modularity of code.
• Polymorphism: Polymorphism is the ability of an object to take on multiple forms. The online c++ compiler achieves polymorphism through function overloading and operator overloading. Function overloading allows a class to have multiple functions with the same name, but with different parameters. Operator overloading allows operators, such as "+" and "-" to be redefined to operate on objects of a specific class.
• Encapsulation: Encapsulation is the process of hiding the implementation details of a class from the outside world. In C++, encapsulation is achieved by using access specifiers, such as "private" and "public". Member functions and data members declared as private can only be accessed within the class, while member functions and data members declared as public can be accessed from outside the class.

These are the fundamental concepts of OOPS in C++. OOP has become a popular programming paradigm because it promotes modularity, code reuse, and easy maintenance of code. It allows for the creation of large and complex programs by organizing code into reusable objects and provides a way to structure code in a way that makes it easy to understand and modify.

Classes

Classes are a fundamental concept of Object-Oriented Programming (OOP) in C++, and play a significant role in organizing and structuring code.

1. Encapsulation: Classes allow for encapsulation, which means that the implementation details of a class can be hidden from the outside world. This makes it easier to maintain and modify code because changes can be made to the class without affecting other parts of the code that use the class.
2. Reusability: Classes can be reused across different program parts, making it easier to write and maintain large and complex programs. By encapsulating related data and functions within a class, code can be organized and reused in a modular way.
3. Abstraction: Classes allow for abstraction, which means that only the essential details of a class need to be known in order to use it. This makes it easier to write code because the implementation details of a class can be hidden from the user, and the user only needs to know how to use the class, not how it works.
4. Polymorphism: In the online c++ compiler classes enable polymorphism, which means that objects of different classes can be used interchangeably in a program. This allows for more flexible and dynamic code and makes it easier to write code that can handle a variety of different objects.

In C++, classes provide a way to organize and structure code into reusable and manageable pieces. By using classes, a program can be divided into smaller, more manageable parts that can be easily reused and modified. The use of classes makes it easier to write and maintain code and helps to promote good software design practices.        

Objects

Objects are instances of classes in Object-Oriented Programming (OOP) and play a significant role in organizing and structuring code in C++.

1. Data Encapsulation: Objects allow for data encapsulation, which means that the data and functions that operate on that data are combined into a single entity. This makes it easier to manage and maintain data because all of the data and functions related to a specific task are grouped together in an object.
2. Reusability: Objects can be reused across different program parts, making it easier to write and maintain large and complex programs. By encapsulating related data and functions within an object, code can be organized and reused in a modular way.
3. Abstraction: Objects allow for abstraction, which means that only the essential details of an object need to be known in order to use it. This makes it easier to write code because the implementation details of an object can be hidden from the user, and the user only needs to know how to use the object, not how it works.
4. Polymorphism: Objects can be used interchangeably in a program, making it possible to write more flexible and dynamic code. By creating objects of different classes, a program can handle a variety of other objects in a generic way.

In C++, objects provide a way to represent real-world entities and their properties and behaviors. By using objects, a program can be organized into reusable and manageable pieces that can be easily modified and reused. The use of objects makes it easier to write and maintain code and helps to promote good software design practices. 

In conclusion, classes and objects play a crucial role in Object-Oriented Programming (OOP) in C++. Classes provide a way to organize and structure code into reusable and manageable pieces, allowing for encapsulation, abstraction, and polymorphism. Objects are instances of classes and allow for data encapsulation, abstraction, and polymorphism. By using classes and objects, C++ programs can be made more flexible, maintainable, and scalable. They also promote good software design practices, making it easier for developers to write and maintain complex and large programs. In short, classes and objects are a fundamental aspect of OOP in C++ and play a significant role in organizing and structuring code.