The Concept of Objects and Classes
The principal elements in Object Oriented Programming are objects and classes. The fundamental building block of an object is its class. This means that you can create any kind of object based on the class defined. While defining a car class, you outline certain characteristics (which can also be said as attributes or fields) as well as possible functions (which are usually methods). When a class has been created, any number of its instances called objects may be created. Each of these objects is capable of retaining its own state and performing its own unique functions.
For instance, suppose that there is a `Car` class. The class could include color, model and year as properties and starting the engine or horn as the behavior. In this case, every particular car example, ie red toyota or blue honda will be an object of this class.
Encapsulation: Data and Implementation Hiding
In the context of object-oriented programming, the concept known as encapsulation can perhaps be termed as one of the most important concepts. It is the concept of bundling the data (properties) and the methods (functions) that operate on that said data into a single unit, referred to as a class. Encapsulation also includes restricting certain aspects of the object’s data structure, a concept referred to as data hiding.
C++ employs several possible mechanisms for implementing encapsulation including the use of access specifiers such as private, protected, and public. These are the mechanisms that specify the degree of exposure of class members. The members of the class that are labeled as private cannot be accessed from anywhere outside the class, thus allowing data to be accessed or altered only through the public methods. This regulates how the data of an object may be fetched or modified.
Encapsulation also tends to ensure that an object will protect the pertinacity of its attributes by ensuring that the object’s internal attributes can not be accessed meaning that the chance of interference is limited. For example, using a class “Car”, the internal state of the engine may not be controllable directly via direct interaction with the car object. Rather methods like `startEngine()` or `stopEngine()` can be made public, thereby allowing control over the car in an indirect manner.
Inheritance: The Concept of Code Reuse
Inheritance is one of the favorite features in OOP which allows implementing one class in another. This enables a programmer to build on existing codes and improve its function without changing its logic. Inheritance exemplifies a ‘is-a’ relationship where the subclass explains the parent class to a finer degree.
In C++, the keyword `public` is used a lot especially in the context of public inheritance which ensures that all the public sections of the parent class are also present in the child class. For instance, suppose a base class “Vehicle” has some parameters such as `color`, `make` and `model`. Then you can consider creating a base class as “Car” which is more detailed in nature. Thus, the “Car” class can inherit these generics and append more specific concepts such as `airConditioning` or `numberOfDoors`.
This type of relationship in computing also encourages the reuse of codes which leads to a more complete class hierarchy. This makes resolving the dependencies and disassociation between the classes occurring in your program much simpler and easier.
Polymorphism: Multiple Methods of Getting the Task Done Through One Interface
Polymorphism is the quality of an object to exist in more than one form. With regard to OOP, polymorphism allows the use of one interface for a set of classes. It also means that multiple functions can share the same name but will perform differently depending on the object that invokes them. In C++, polymorphism is mainly implemented by the mechanisms of function overloading and function overriding.
- Function overloading is a feature that allows different functions to use the same name if they have a different number of arguments (or a different type of arguments). The final decision as to which function to execute is up to the compiler depending on how many of the types of arguments have been presented.
- Function overriding occurs when a subclass provides a specific implementation of a method which has been provided in a parent class. The child class method provides the more specific implementation while the method in the parent class provides the general purpose one.
Polymorphism enables programmers to write code that is more flexible and more reusable. For example, a `draw()` function could be implemented for any shape even if those shapes include circles and rectangles or any other shape. However, the drawing itself is specific to the shape of the object. In this program, a `draw()` function can be executed on any object received that is derived from the main class “Shape” and the relevant function for `draw()` is executed depending on the shape of the object.
Abstraction: Hiding Internal Details With Simplification
Abstraction is as much about eliminating unnecessary details as it is about encapsulating important features. Such level of complexity is manageable because developers are provided with low level interfaces such as `class` and `object`. Hence the user might not be interested in the inner workings of an object, but rather what an object is capable of. In C++, the principle of abstraction is most often employed with the help of abstract classes and pure virtual functions.
An abstract class cannot be used alone because it is not suitable for instantiation. Rather it exhibits the design of other classes that can make use of it. One or more pure virtual functions may reside in this class which are undeclared in the abstract class but require definition in classes that are derived from the abstract class. Such practice guarantees that all derived classes implement their version of the abstract function.
Abstraction is essential in handling large systems as it helps focus on the general operations and ignores the operative details. For instance, a PaymentProcessor class will encapsulate a method called processPayment and its functionality will be varied in a number of extending classes like CreditCardPayment or PayPalPayment, which will provide the specifics of the implementation.
What OOP is and How it Differs from the Rest
Object-Oriented Programming provides order to the jumble of C++ code which is the case mostly in large and complex projects. Likewise, from everyday experience, C++ programmers can construct class objects and methods to approach the system in a comprehensible, simplified manner. This can be done with the help of inheritance and polymorphism which allow reusability of code and adaptable design, while encapsulation and abstraction maintain the premise that the code is optimized for modification and troubleshooting.
C++ comes with great means of observing the principles of OOP, and learning those principles comes handy for writing reasonably-portable, efficient, and highly-readable code. Be it a basic application such as a notepad or a complicated and distributed system, using and understanding OOP concepts will bring order and rationale into the final product implemented.
