C++ Classes, Objects, and OOP Principles
Class
A class is a blueprint or template for creating objects. It defines a set of attributes and methods that the objects created from the class will have. A class encapsulates data for the object and methods to manipulate that data.
Object
An object is an instance of a class. It represents a unique occurrence of the class, with its own set of attributes (variables) and methods (functions). Objects are created from classes, following the blueprint provided by the class.
Constructors in C++
In C++, constructors are special member functions of a class that are automatically called when an object of that class is created. They are used to initialize the object’s data members and prepare the object for use. Here are the key points about constructors in C++:
Default Constructor
A default constructor is a constructor that doesn’t take any arguments. If you don’t define a constructor for your class, C++ provides a default constructor automatically. Its purpose is to initialize data members with default values.
class MyClass {
public:
MyClass() {
}
};Parameterized Constructor
A parameterized constructor is one that accepts parameters to initialize the object with specific values. You can define multiple constructors with different parameter lists, allowing for object initialization in various ways.
class Person {
private:
std::string name;
int age;
public:
Person(const std::string& n, int a) : name(n), age(a) {
}
};Destructor
A destructor in C++ is a special member function of a class that is automatically called when an object of that class is destroyed. Its primary purpose is to clean up resources allocated by the object during its lifetime, such as memory allocated with new or resources acquired using system calls.
Encapsulation
Encapsulation is one of the fundamental principles of object-oriented programming (OOP) that promotes data hiding and abstraction. It involves bundling the data (attributes or variables) and the methods (functions) that operate on the data into a single unit called a class. Encapsulation allows for better control over access to the data and protects it from unauthorized modification.
Abstraction
Abstraction is a fundamental concept in object-oriented programming (OOP) that involves hiding the complex implementation details of a system while exposing only the essential features or functionalities to the outside world. It focuses on what an object does rather than how it does it, thereby simplifying the interaction with the object and reducing complexity in software development.
Inheritance
Inheritance in object-oriented programming (OOP) is a mechanism where a new class (derived class) is based on an existing class (base class or parent class). The derived class inherits attributes and methods from the base class, allowing code reuse and promoting a hierarchical relationship between classes.
Polymorphism
Polymorphism is a fundamental concept in object-oriented programming (OOP) that allows objects to be treated as instances of their parent class or any of their subclasses interchangeably. It enables code to work with different types of objects through a single interface, providing flexibility and extensibility to the software.
Runtime Polymorphism
Runtime polymorphism, also known as dynamic polymorphism, is a key feature of object-oriented programming (OOP) that allows a subclass to provide a specific implementation of a method that is already defined in its superclass. This enables objects of different classes to be treated as objects of their common superclass, providing flexibility and extensibility to the code.