Abstraction in Object-Oriented Programming

Class and Object

• A class is a user-defined data type that contains functions and is a blueprint for objects.
• A class declares and defines the data variables and operations that can be performed on its objects.
• An instance of a class is an object, similar to a house built from a blueprint.

Abstraction

• Abstraction shows only the essential features of an application and hides the details.
• In C++, classes provide methods to access and use data variables, but the variables are hidden from direct access.

Encapsulation

• Encapsulation binds data variables and functions together in a class.
• It is also known as data binding.
• Access specifiers can be used to control access to the data variables.

Inheritance

• Inheritance is a way to reuse code by creating a new class based on an existing class.
• The existing class is called the base class, and the new class is called the derived class.
• The derived class can use all the functions defined in the base class.

Polymorphism

• Polymorphism allows functions with the same name to have different arguments and perform differently.
• It also allows functions to be redefined to provide new definitions.

Exception Handling

• Exception handling is a feature of OOP that handles unresolved exceptions or errors produced at runtime.

UML and Class Diagram

• The primary goals of UML include providing a ready-to-use visual modeling language, extensibility, and independence from programming languages.
• A class diagram is a central modeling technique in OOP that describes the types of objects in a system and their relationships.
• There are three principal kinds of relationships in class diagrams: association, inheritance, and aggregation.

Object-Oriented Programming (OOP)

• OOP is a way of programming that enables programmers to think like they are working with real-life entities or objects.
• Objects have fields to store knowledge/state/data and can do various works — methods.
• OOP features include classes, objects, inheritance, polymorphism, abstraction, and encapsulation.

Merits and Demerits of OOP

• The merits of OOP include code reusability, modularity, and ease of maintenance.
• The demerits of OOP include increased complexity and difficulty in debugging.

Learning Objectives

• To understand the relative merits of C++ as an OOP language.
• To understand the features of C++ that support OOP.
• To demonstrate the concepts of UML and class diagram in OOP.
• To demonstrate the concept of functions in OOP.