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Object-Oriented Programming (OOP) is a programming paradigm that organizes code into objects, which combine data (attributes) and behavior (methods).
OOP enables you to model your programs using real-world objects. This will not only help you think more abstractly, it'll also make your code more robust, easier to debug and easier for others to modify.
Encapsulation
Bundles data and methods that operator on the data within one unit (class).
Protects object state by restricting direct access to internal state using access modifiers (e.g., private, protected, public).
Abstraction
Hides internal implementation details and exposes only essential parts.
Focuses on what an object does, not how it does it.
Inheritance
Creates new classes from existing ones, allowing a class to acquire properties and behaviors of another class (base class).
Enables code reuse and a hierarchical class structure.
Polymorphism
Allows one interface to be used for different underlying data types.
Achieved via function overloading and overriding (especially with virtual functions).
A class is a blueprint for creating objects that defines data (attributes) and functions (methods) that operate on data.
It does not occupy memory until an object is created.
A class defines the structure and behavior of its objects.
An object is an instance of a class which represents a real-world entity with state (data) and behavior (functions/methods).
Created based on a class (blueprint).
Occupies memory.
Can access the class's members (variables and functions).
A virtual function in C++ is a member function in a base class that you expect to override in derived classes. It enables runtime polymorphism, allowing the correct function to be called based on the object type, not the pointer/reference type.
A virtual function lets you define a function in a base class and override it in derived classes so the correct version is chosen at runtime.
A virtual destructor ensures that when a base class pointer is used to delete a derived class object, both the base and derived destructors are called properly. This is important for proper cleanup and to avoid memory or resource leaks.
You need a virtual destructor whenever a class is intended to be used polymorphically, meaning it has virtual functions or might be deleted through a base class pointer.