As a C++ developer, understanding the fundamental concepts of object-oriented programming (OOP) is essential, as OOP is a core aspect of C++. Here are the basic concepts:
- Classes and Objects:
A class in C++ can be thought of as a blueprint or template for creating objects. It defines properties (data) and behaviors (functions or methods) of an object.
- An object is an instance of a class. It represents a specific realization of the class with its own state defined by the values of its properties.
Encapsulation is about bundling data and methods that operate on that data within a single unit or class.
- It also involves restricting direct access to some of an object’s components, which is a means of preventing accidental interference and misuse of the methods and data.
Inheritance allows a new class to adopt the properties and methods of an existing class.
- This promotes code reusability and establishes a relationship between the new subclass (derived class) and the existing superclass (base class).
- Polymorphism- Polymorphism, in the context of C++, refers to the ability of a function or method to behave differently based on the object that calls it.
- This can be achieved through mechanisms like function overloading and overriding.
- Abstraction means providing only essential information to the outside world while hiding the internal details. It simplifies complex reality by modeling classes appropriate to the problem.
- This is achieved by defining classes that represent abstract data types that can perform work for the user.
- Constructor and Destructor
- Constructors are special class functions which are called automatically when an object is created. They are used to initialize the object’s properties.
- Destructors are used to deallocate resources held by the object when it is no longer needed.
- Member Functions and Attributes
- Member functions are functions defined inside a class and are used to access object data.
- Member attributes are the data (variables) contained within a class.
- Method Overloading and Overriding- Overloading occurs when two or more methods in one class have the same method name but different parameters.
- Overriding is redefining a method in a derived class where it was already defined in the base class.
These concepts form the foundation of object-oriented programming in C++. They enable developers to create modular, reusable, and more manageable code. In practice, these concepts are interrelated and are used together to design robust and efficient software systems.
Object-oriented programming (OOP) is a balanced approach to writing software in which data and behavior are packaged together. This encapsulation
creates user-defined types, extending and interacting with the native types of the language.
The term OOP refers to a collection of concepts, including the following:
- User-defined types can be easily created and used.
- Implementation details of user-defined types are hidden.
With OOP, the programming task is frequently more difficult than normal procedural programming, such as in C.
There is at least one extra design step before you get to the coding of algorithms. This extra step involves the design of types that are appropriate for the problem at hand. Frequently, you must solve a problem more generally than is strictly necessary.
The belief is that this will pay dividends in several ways:
- The solution will be more self-contained and thus, more robust and easier to maintain and change.
- The solution will be more reusable.
You define a new data type by defining a class, but before I get into the language, syntax, and programming techniques of classes, I will explain how your existing knowledge relates to the concept of object-oriented programming. Almost everything you have seen up to now has been procedural programming, which involves programming a solution in terms of fundamental data types. The essence of object-oriented programming
(commonly abbreviated to OOP) is that you write programs in terms of objects in the
of the problem you are trying to solve, so part of the program development process involves designing a set of types to suit the problem context. If you are writing a program to keep track of your bank account, you will probably need to have data types such as Account and Transaction. For a program to analyze baseball scores, you may have types such as Player and Team. The variables of the fundamental types do not allow you to model real-world objects very well. It is not possible to model a baseball player realistically in terms of just an int or double, value or any other fundamental data type.
You need several values of a variety of types for any meaningful representation of a baseball player. Classes provide a solution. A class type can be
- a composite of variables of other types of fundamental types or
- of other class types.
A class can also have functions as an integral part of its definition. You could define a class type called Box that contains variables that store a length, a width, and a height to represent boxes. You could then define variables of type Box, just as you define variables of fundamental types. Each Box object would contain its own length, width and height dimensions and you could create and manipulate as many Box objects as you need in a program.