What is the usage of classes in C++?
Class in C++ is a user-defined data type that encapsulates a collection of data members (attributes) and member functions (methods), serving as a template for creating objects (instances).
The main uses of the class include the following aspects:
- Defining a class: Use the keyword class and the class name to define a class. You can define member variables and member functions in the class, and use access modifiers (public, private, protected) to restrict access to members.
- Creating objects: using the class name and constructor to instantiate objects of the class. Objects are instances of the class, and they have the properties and methods defined within the class.
- Accessing member variables and member functions: Use the object name and the member access operator “.” to access the class’s member variables and member functions. The dot operator can be used to access public member variables and public member functions, while private members can only be accessed within the class.
- Constructor and destructor: The constructor is used to initialize the properties of an object and is automatically called when the object is created. The destructor is automatically called when the object is destroyed, and is used to clean up the resources used by the object.
- Inheritance in classes: Declare a derived class (subclass) by using the keyword “class” followed by a colon and the base class name. The derived class inherits the properties and methods of the base class and can add new properties and methods.
- Access control: Use access modifiers (public, private, protected) to control access to members. Public members can be accessed from outside the class, private members can only be accessed within the class, and protected members can be accessed in derived classes.
- Static members of a class include static member variables and static member functions. These members belong to the class itself rather than instances of the class, and can be accessed directly using the class name without needing to create an object.
- Friend functions of a class can be declared using the keyword “friend”, allowing them to access the private members of the class.
Classes are one of the core concepts of object-oriented programming in C++, providing a mechanism for encapsulation and abstraction that makes code more modular and reusable.
