Classes and Objects

 Learning Objective

• Learn about classes, private, protected, and public members of a class

• Explore how classes are implemented

• Become aware of accessor and mutator functions

• Examine constructors and destructors

• Learn about the abstract data type (ADT)

• Explore how classes are used to implement ADTs

• Learn about information hiding

• Explore how information hiding is implemented in C++

• Learn about the static members of a class

In modern programming, organizing code modular and reusable is essential for managing complexity, especially in large projects. C++ offers powerful features for achieving this through Object-Oriented Programming (OOP). At the heart of OOP are classes and objects—fundamental concepts that enable you to model real-world entities and relationships in your code.

This chapter will introduce you to the concepts of classes and objects, laying the foundation for the entire study of C++ data structures. Understanding classes and objects is crucial because they are the building blocks of more complex data structures and algorithms. Here’s what you will learn in this chapter:

Key Concepts:

1. What is a Class?

   • A class is a blueprint for creating objects (a particular data structure). It encapsulates data for the object and methods to manipulate that data. By defining classes, you can model real-world entities such as a Car, Student, or BankAccount in your programs.

   • We'll explore how to define a class in C++ and understand its key components—data members and member functions.

2. What is an Object?

   • An object is an instance of a class. When you create an object, you essentially bring the blueprint to life. Objects represent the specific instances of a class with actual values, allowing you to interact with your code meaningfully.

   • You'll learn how to create objects in C++, access their attributes, and call their methods.

3. Encapsulation

   • Encapsulation is the bundling of data and the methods that operate on that data within one unit, a class. This concept helps protect an object's internal state and ensures that its data can only be modified in controlled ways.

   • We will discuss the role of access specifiers (public, private, and protected) in enforcing encapsulation.

4. Constructors and Destructors

   • Constructors are special member functions used to initialize objects. They are called every time an object is created. We will explore different types of constructors, including default constructors, parameterized constructors, and copy constructors.

   • Destructors, on the other hand, are special member functions called when an object is destroyed. They perform any necessary cleanup before an object is removed from memory.

5. Member Functions

   • Member functions are functions defined within a class that operate on the class's data members. We'll cover the syntax for defining and calling member functions and explore the concept of const member functions.

6. Static Members

   • Static members of a class are shared among all instances of that class. We will learn about static data members and static member functions and understand how they differ from regular class members.

7. Object-Oriented Principles

   • We'll touch on key object-oriented principles like abstraction, inheritance, and polymorphism, which you will encounter in more depth later in the textbook. These principles are essential for building scalable and maintainable software.

Why Classes and Objects Matter:

Understanding classes and objects is critical for mastering C++. They form the foundation upon which more advanced topics, such as data structures, are built. By mastering the concepts of classes and objects, you'll be equipped to design and implement complex data structures that are both efficient and easy to maintain.

In this chapter, we will start with the basics, ensuring you have a strong grasp of these core concepts before moving on to more advanced topics. By the end of this chapter, you should be comfortable with defining your own classes, creating objects, and utilizing object-oriented programming principles in your C++ programs.