Introduction to OOPs

Object-oriented programming is a type of programming which is based on objects rather than functions and procedures. In OOPs, everything treated as object.

Features of oops/characteristics –

Class
Object
Encapsulation
Abstraction
Polymorphism
Inheritance

Class

Programming Language Programming language is a way to communicate with computer system, just we communicate to each other using Hindi or English language.

There are two type of programming languages

→ 1. Function oriented programming languages Example – C Programming

→ 2. Object-Oriented programming language

2.1. Object based – C++, Java, Python
2.2 Object-Oriented – Visual Basic,
2.3 Pure object-oriented programming
language only one have – SMALLTALK.

Class

A class is a blueprint or template that defines the structure, behavior, and attributes of objects. It is a conceptual representation of a real-world entity or a logical entity in a program. A class acts as a blueprint from which objects, also known as instances, can be created.

Class is a user-defined data type
Class is an abstract data type
Class is a keyword in Java

class Student {

}

Syntax:
class Class_Name       // class - keyword , ClassName - user-defined name
{
    access specifier         // can be private, public or protected
    Data member           // variable to be used
    Member Function() {}  // method to access data member
};                             // class name ends with a semicolon

// real world example
#include <bits/stdc++.h>
using namespace std;

class Student {
    // private and public are access specifier/modifier
    // data member
    private:
    int age;
    public:
    string name;
    string gender;

    // constructor initialize member of class
      public:
Student(string name, string gender, int age) {
        this->name = name;
        this->gender = gender;
        this->age = age;
    }

    // public member method used to display information of student
    void displayInfo() {
        cout << "Name of student is : "<< name << endl;
        cout << "Gender of student is: " << gender << endl;
        cout << "Age if student is: " << age << endl;
    }
};

int main() {
    // here s1 is object of Student class
    Student s1("Heera Singh Lodhi", "Male", 20);
    s1.displayInfo();
    return 0;
}

/*
Output
Name of student is : Heera Singh Lodhi
Gender of student is: Male
Age if student is: 20

*/

Object

An object is an instance of a class. It represents a specific entity in the real world, and it encapsulates both data (properties or attributes) and behaviour (methods).

Object is a run time entity.
Object is a physical entity.
Object is real world entity.
Object is a collection of member variable.
Object stored into heap area.
Heap is a part of main memory (RAM).

Class​

Class​

Object​

Class

Class

Object