OOPS Concepts in C++

               OOP – Object Oriented Programming. It is a programming approach which deals with objects and classes. It creates reusable code to achieve modularity.

Why OOPs concepts?

• It makes the code modular.
• The code can be reusable any times.
• It is scalable.
• It gives you security from unauthorized access.

OOPs concepts:

The concepts are listed below.

1. Class
2. Object
3. Abstraction
4. Encapsulation
5. Polymorphism
6. Inheritance

Each one of the concepts are explained with code as follows…

1.Class:

              It is a prototype from which the object are created. It has a collection of variables and methods.you can create multiple objects for single class. The class has following components.

Class Components:

• Class name: Name of the class.
• Access specifiers: private, public and protected
• Methods: it defines the functionalities.
• Variables: it deals with values.
• Constructors: it initializes the values.
• Body: it contains the code of the class.

Eg:

Class class_name {

Access specifier:

 Datatype variable1;

…………………………….

 Datatype variablen;

Access specifier:

Constructor:

……………………..

//get() methods

……………………..

//set() methods

………………………

//other methods

……………………….

}

main()

{

………………………

}

2. Object:

   An object is a real world entity. Using the class, the objects are created. The object has some properties.

State: The data members reflects for the object.

Behaviour: it is response of object to other objects.

Member function: it performs a specific task.

Identity: it is the unique name of object.

Let us create a c++ program to use class and object.

C++ program:

#include <iostream>

#include <string>

using namespace std;

class Student {

// variable declaration

private:

    string s_name;

    string s_id;

    string s_year;

 public:

    // Constructor initialisation

    Student(string s_name,string s_id,string s_year) {

        this->s_name = s_name;

        this->s_id = s_id;

        this->s_year = s_year;

    }

     // get methods

    string getName() { return s_name; }

    string getId() { return s_id; }

    string getYear() { return s_year;}

     // set methods

    void setName(string s_name) { this->s_name = s_name; }

    void setId(string s_id) { this->s_id= s_id; }

    void setYear(string s_year) {this->s_year;}

    // Instance method

    void displayIt() {

        cout << "Name: " << s_name << endl;

        cout << "Id: " << s_id << endl;

        cout << "Year: "<< s_year <<endl;

    }

};

 int main() {

    string s_name,s_id,s_year;

    cout<<"Enter the details:"<<endl;

    cout <<"Enter the name: " <<endl;

    cin>>s_name;

    cout <<"Enter the id: " <<endl;

    cin>>s_id;

    cout <<"Enter the year: " <<endl;

    cin>>s_year;

    Student ss(s_name,s_id,s_year);

    ss.displayIt();

    return 0;

}

Output:

Enter the details:

Enter the name:

Jey

Enter the id:

Q1

Enter the year:

I

Name: Jey

Id: Q1

Year: I

This is the basic of OOPs concept. In this blog, class and object are explained with examples. Remaining concepts are explained in next post.