The Project | About Us | Contribute | Donations | License
HOME My courses Completed
◄ Previous
◄

Introduction to OOP

Next ►
►

Object-Oriented Programming (OOP) is a programming paradigm that uses "objects" to design applications and computer programs. It utilizes several key concepts such as classes, objects, inheritance, polymorphism, encapsulation, and abstraction. This module will introduce you to these fundamental concepts and how they are implemented in C++.

Key Concepts of OOP

  1. Classes and Objects

    • Class: A blueprint for creating objects. It defines a datatype by bundling data and methods that work on the data into one single unit.
    • Object: An instance of a class. When a class is defined, no memory is allocated until an object of that class is created.

  2. Inheritance

    • A mechanism by which one class can inherit the properties and methods of another class. This promotes code reusability.

  3. Polymorphism

    • The ability of a function, object, or method to take on multiple forms. It allows one interface to be used for a general class of actions.

  4. Encapsulation

    • The bundling of data and methods that operate on the data within one unit, e.g., a class. It restricts direct access to some of the object's components, which can prevent the accidental modification of data.

  5. Abstraction

    • The concept of hiding the complex implementation details and showing only the necessary features of an object.

Practical Example: Creating a Simple Class

Let's start with a simple example to illustrate the basic concepts of classes and objects.

Example: Defining a Class and Creating an Object

#include <iostream>
using namespace std;

// Define a class named 'Car'
class Car {
public:
    // Data members
    string brand;
    string model;
    int year;

    // Member function
    void displayInfo() {
        cout << "Brand: " << brand << endl;
        cout << "Model: " << model << endl;
        cout << "Year: " << year << endl;
    }
};

int main() {
    // Create an object of Car
    Car car1;

    // Accessing data members and assigning values
    car1.brand = "Toyota";
    car1.model = "Corolla";
    car1.year = 2020;

    // Calling member function
    car1.displayInfo();

    return 0;
}

Explanation

  1. Class Definition: The Car class is defined with three public data members (brand, model, and year) and one public member function (displayInfo).
  2. Object Creation: An object car1 of the Car class is created.
  3. Accessing Members: The data members of car1 are accessed and assigned values.
  4. Calling Member Function: The displayInfo function is called to print the car's details.

Exercise: Create Your Own Class

Task: Define a class named Book with the following specifications:

  • Data members: title, author, yearPublished
  • Member function: displayDetails to print the book's details

Solution:

#include <iostream>
using namespace std;

class Book {
public:
    string title;
    string author;
    int yearPublished;

    void displayDetails() {
        cout << "Title: " << title << endl;
        cout << "Author: " << author << endl;
        cout << "Year Published: " << yearPublished << endl;
    }
};

int main() {
    Book book1;

    book1.title = "1984";
    book1.author = "George Orwell";
    book1.yearPublished = 1949;

    book1.displayDetails();

    return 0;
}

Common Mistakes and Tips

  • Access Specifiers: Ensure that the data members and member functions are correctly specified as public or private based on the requirement.
  • Initialization: Always initialize your objects before using them to avoid undefined behavior.
  • Function Calls: Ensure that member functions are called using the object of the class.

Conclusion

In this section, we introduced the basic concepts of Object-Oriented Programming and demonstrated how to define a class and create an object in C++. We also provided a practical example and an exercise to reinforce the concepts. In the next section, we will delve deeper into classes and objects, exploring constructors and destructors.

◄ Previous
◄
Next ►
►
The Project | About Us | Contribute | Donations | License
© Copyright 2024. All rights reserved