Features of Object Oriented Programming Part 2 | C ++ Tutorial | Mr. Kishore

Summary

This video script by Kishore from Nares introduces the fundamental concepts of Object-Oriented Programming (OOP). It explains the core features of OOP, such as classes, objects, data hiding, encapsulation, inheritance, and polymorphism. The script delves into the comparison between C structures and C++ classes, highlighting the extension of structures into classes with added benefits like data protection and the ability to design complex applications. It also clarifies the difference between structures and classes in C++, emphasizing the private access specifier in classes for secure data handling and the role of member functions in accessing private data, encapsulating the principles of data hiding and encapsulation.

Takeaways

• 😀 Object-Oriented Programming (OOP) is a programming paradigm that uses 'classes' and 'objects' to design applications.
• 🏫 The concept of 'class' in OOP is an extension of the C structure, allowing the bundling of data and functions together.
• 🔒 Data hiding in OOP is achieved by using private access specifiers, restricting access to class data members to only member functions within the same class.
• 📦 Encapsulation is the process of binding data and associated functions into a single unit, which is the class, providing a way to bundle data and methods that operate on the data.
• 🔑 Inheritance is a key feature of OOP that allows a new class to inherit properties and behaviors (methods) from an existing class.
• 📈 Polymorphism allows objects to be treated as instances of their parent class rather than their actual class, enabling a single interface to be used for a general class of actions.
• 🔄 Message communication is the mechanism by which objects interact with each other in OOP, typically through method calls.
• 📌 The 'structure' in C language is a collection of heterogeneous variables and is the foundation for OOP concepts, but lacks data protection and complex program design capabilities.
• 🔄 C++ extends the concept of structures by allowing the declaration of member functions and access specifiers, but still has the limitation of public data by default.
• 🛡️ The introduction of 'class' in C++ addresses the shortcomings of structures by providing private, protected, and public access levels, enhancing data security and supporting complex program design.
• 🔍 An object in OOP is an instance of a class, representing the physical manifestation of the class blueprint, with allocated memory for its data members when created.

Q & A

What does OOP stand for and what are its main features?

OOP stands for Object-Oriented Programming. Its main features include class, object, data hiding, encapsulation, inheritance, polymorphism, and message communication.

What is a class in the context of OOP?

A class in OOP is an extension of a C structure. It is a user-defined data type that allows the bundling of data and functions together into a single unit, which can then be used to create objects.

What is the difference between a C structure and a C++ structure?

In C, structures can only contain variables, whereas in C++, structures can also contain member functions along with variables. However, by default, both C and C++ structures have public data members, which can be accessed from anywhere in the program.

Why were classes introduced in C++?

Classes were introduced in C++ to address the issue of data protection that is not available in structures. Classes allow for the encapsulation of data and functions, and they support access specifiers like private, which restrict access to class members from outside the class.

What is the concept of data hiding in OOP?

Data hiding in OOP is the practice of making class data members private, so they can only be accessed and modified by the class's member functions. This prevents unauthorized access and modification of the data from outside the class.

What is encapsulation and how is it achieved in a class?

Encapsulation is the process of binding data and the associated functions together into a single unit or class. It is achieved by declaring data members and member functions within a class and using access specifiers to control access to these members.

What is an object in OOP?

An object in OOP is an instance of a class. It is a variable of the class type and represents the physical manifestation of the class blueprint, holding actual data and being able to perform actions defined by its member functions.

How does a class act as a blueprint for creating objects?

A class acts as a blueprint by defining the structure and behavior of the objects that can be created from it. When an object is instantiated from a class, memory is allocated for the object's data members, and the object can access the class's member functions.

What is the default access level for members in C++ classes and structures?

In C++, the default access level for members in a class is private, whereas in C++ structures, the default access level is public.

Why are structures not suitable for designing large applications?

Structures are not suitable for designing large applications because they do not support the concept of inheritance, which is crucial for creating extensible and maintainable code in large projects. Classes, on the other hand, support inheritance along with encapsulation and data hiding.

Can you access private data members of a class from outside the class?

No, private data members of a class cannot be accessed from outside the class. They can only be accessed and modified through the class's member functions, ensuring data hiding and encapsulation.

Outlines

00:00

📘 Introduction to Object-Oriented Programming Concepts

This paragraph introduces the concept of Object-Oriented Programming (OOP), explaining its fundamental features such as class, object, data hiding, encapsulation, inheritance, polymorphism, and message communication. It emphasizes the importance of the 'class' concept, which extends the C structure, allowing for the grouping of heterogeneous variables under one name. The paragraph sets the stage for a deeper dive into the specifics of OOP, starting with the class concept and its relation to C structures.

05:01

🏭 Understanding C Structures as the Foundation of OOP

The speaker elaborates on C structures, which serve as the basis for OOP. A structure is a user-defined data type that can hold a collection of heterogeneous variables, making it an essential component for constructing objects in OOP. The paragraph provides an example of a 'student' structure, illustrating how it can store a student's ID, name, and subject-wise marks. It also discusses the memory allocation for structure variables and the process of accessing structure members. However, it points out the limitation of C structures, which is the lack of data protection due to public accessibility by default.

10:04

🔒 Transitioning from C Structures to C++ Classes for Enhanced Data Security

This paragraph discusses the transition from C structures to C++ classes, highlighting the introduction of data encapsulation and access specifiers like private, public, and protected in C++. It explains that while C++ structures can include member functions and have access specifiers, they lack the capability for complex program design and do not support inheritance, unlike classes. The paragraph emphasizes the importance of classes in C++ for creating secure and scalable applications due to their ability to restrict data access and support object-oriented features like inheritance.

15:07

🔑 The Role of Classes in Data Hiding and Encapsulation

The speaker explains the concept of data hiding and encapsulation in the context of C++ classes. Data hiding is achieved by declaring class members as private, restricting access to them by outside entities and allowing access only through member functions of the same class. Encapsulation is described as the bundling of data members and member functions into a single unit, which is the class. The paragraph provides an example of a 'student' class with private data members and a public member function to access them, illustrating how classes facilitate secure and organized code design.

20:09

🏗️ Class as a Blueprint and Object as an Instance in OOP

This paragraph delves into the distinction between classes and objects in OOP. It describes a class as a blueprint or an original copy from which multiple instances, or objects, are created. The class defines the structure and behavior of the objects, while objects are the actual instances that carry out the class's defined actions and store its data. The speaker uses the analogy of a blueprint for a building to explain the relationship between classes and objects, emphasizing that memory is allocated for objects only when they are created, not when the class is defined.

25:10

🎭 The Physical Representation of Objects in OOP

The final paragraph reinforces the concept of objects as the physical representation of a class. It reiterates that classes are logical constructs defining the properties and methods, while objects are the tangible entities that embody these definitions. The speaker likens the class to a blueprint and objects to the actual copies or instances made from that blueprint. This paragraph wraps up the session by summarizing the key points discussed about OOP features and their significance in software development.

Keywords

💡Object-Oriented Programming (OOP)

OOP stands for Object-Oriented Programming, a programming paradigm that uses 'objects' to design applications and software. It is the central theme of the video, as it discusses the features and concepts of OOP. The script explains that OOP is based on the idea of a 'class', which is a blueprint for creating objects, and it also covers other key OOP features like inheritance and encapsulation.

💡Class

In the context of the video, a 'class' is defined as an extension of the C structure, serving as a blueprint for creating objects. It is a user-defined data type that allows the bundling of data and functions together. The script illustrates the concept of a class by comparing it to a structure in C, highlighting that classes in C++ can include both data members and member functions, unlike C structures.

💡Object

An 'object' is an instance of a class. The video script explains that objects are created from classes and are variables of a class type. They represent the physical manifestation of the class blueprint, allocating memory for the data members defined in the class. The script uses the example of a 'student' to illustrate how objects store related data for individual instances.

💡Data Hiding

Data Hiding is a principle in OOP that restricts direct access to some of an object's components, which is a form of encapsulation. The video script discusses how in C++, class data members are private by default, meaning they can only be accessed through member functions of the same class. This concept is crucial for creating secure and modular code.

💡Encapsulation

Encapsulation is the process of bundling the data (attributes) and methods (functions) into a single unit or class. The video script explains that encapsulation is achieved by using private access specifiers in classes, which bind data and functions together, preventing unauthorized access and maintaining integrity.

💡Inheritance

Inheritance is a fundamental concept in OOP that allows a new class to take on the properties and methods of an existing class. Although not explicitly detailed in the script, it is mentioned as one of the OOP features, and it is implied that classes facilitate inheritance, unlike C structures.

💡Polymorphism

Polymorphism is another key OOP feature that allows objects to be treated as instances of their parent class rather than their actual class. The script mentions polymorphism as one of the features of OOP, suggesting that it is a concept that enables objects to be used interchangeably in the context of a program.

💡Message Communication

Message Communication refers to the method by which objects interact with each other in OOP. The script lists it as one of the OOP features, indicating that it is a way for objects to send and receive messages, which is a form of inter-object communication.

💡Structure

A 'structure' in C is a collection of heterogeneous variables, allowing different types of variables to be stored under one name. The video script uses the concept of structures to lay the foundation for understanding classes in C++. It explains that structures in C are public by default and do not support functions, which is a limitation that classes overcome.

💡User-Defined Data Type

The term 'user-defined data type' is used in the script to describe structures and classes, which are types that are not built into the language but are created by the programmer to suit specific needs. The script explains that structures and classes are user-defined because they allow the programmer to define how data is organized and accessed.

💡Member Function

A 'member function' is a function declared inside a class in C++. The script explains that member functions are used to access the private data members of a class. They are an integral part of encapsulation, as they provide the only means of accessing and modifying private class data.

Highlights

Introduction to Object-Oriented Programming (OOP) and its features such as class, object, data hiding, encapsulation, inheritance, polymorphism, and message communication.

Explanation of 'class' as an extension of C structures, emphasizing the role of structures as the foundation for OOP.

Description of a structure as a collection of heterogeneous variables, allowing for the storage of different types of variables under one name.

Differentiation between primitive and derived data types in C language, with structures allowing the declaration of both types.

The concept of user-defined data types, with structures being an example due to their customizable nature based on requirements.

Illustration of how to use structures to store related data, such as student data including ID, name, and subject-wise marks.

The problem with C structures being that their data is public by default, leading to a lack of data protection.

Introduction of the class concept in C++ to address the issue of public structure data and to enable secure data handling.

Difference between C and C++ structures, with C++ allowing the declaration of member functions and access specifiers within structures.

The inherent issue with C++ structures being unable to design complex programs due to their public data by default.

The class in C++ as a blueprint for creating objects, with private data members being accessible only through member functions.

Concept of data hiding in classes, achieved by making data members private and accessible only via member functions.

Encapsulation defined as the binding of data members and member functions into a single unit, which is the class.

The role of objects as instances of a class, representing the physical realization of the logical class blueprint.

Explanation of how objects are created from classes and how memory is allocated for them, distinguishing between class and object.

The remaining OOP features to be covered in the subsequent session, indicating a continuation of the topic.

Transcripts

[Music]

welcome to Nares this is Kishore and

today we are going to start object

oriented Futures yesterday we have

discussed one concept that is what

objectoriented programming okay now we

are going to start object oriented

features what are the features available

in oops concept means oop oop stands for

objectoriented programming now in oop

concept the first main thing is class

later second one is nothing but object

next data hiding next encapsulation next

inheritance polymorphism message

Communications like this the whoops

features are we're having several okay

we are having several oops features what

they are one is nothing but class now

I'm going to start what is a class and

later we are going to discuss about

object later what is called Data hiding

what is called encapsulation everything

now we are going to start first uh the

whoops future that is nothing but

class now what is a class simply class

is is the extension of C structure okay

then that means we have to discuss about

C structure little bit generally in C

language generally in C language

structure means collection of

heterogeneous variables that means a

structure allows to store different

types of variables at one place under

one name okay okay that's why it is very

easy to construct object oriented

programming okay that's why generally

structures are the foundations for okay

structures are the foundations for

object oriented Concepts that means here

in object oriented programming we are

going to use the class but that class is

derived from means class is the

extension of C structure that's why

first time I'm going to discuss about

the C structure later we are going to

start the class concept now structure

means what it is collection of

heterogeneous variables okay otherwise

in other terms a structure is a user

defined data type and why it is called

user defined data types because of there

is a cause generally in C language we

are going to use some primitive data

types as well as we are going to use use

some derived data types for example

primitive data types means integers

float character now derived data type

means AR pointers and functions now we

are able to declare both

the Primitive and derived data type at

one place using the structure concept

for example I want to store some student

data means I want want to store one

particular student data now generally

every student contains what id number

name subject wise marks generally I have

to declare like this

suppose in ID just assume it is nothing

but the main

function now it is a main function and

the main function contains student ID

next student name

next every student is having subject

wise marks okay for example one student

is having six subjects now I have to

declare what six subjects suppose S1

S2 and

S6 here I have to declare six variables

for six subjects okay instead of this

can I declare array yes it is hone now

now in place of normal variables I'm

going to use

AR okay now here I can declare employee

details everybody that means they're

nonrelated data that means this program

allows to store nonrelated data but I

want to make it related that means I

want to store only the student data at

one place okay then in place of main

function I'm going to start

structure suppose structure name is

student now see this it is the student

structure and the student structure

contains first thing is id id is of

integer type and

S6 actually we are calling array okay

here ID is a normal variable and S is a

array type variable now here the point

is ID is a primitive data type and AR is

a derived data type now we are able to

store both primitive and derived data

type under one name called structure

okay that means the total structure is

constructed by the user based on the

requirement that's why structure is

called it is a user defined data type

that's why structure is called it is a

user defined data type next a structure

is also called complex data type because

of different types of variables are

stored under one name at one place okay

and due to this Advantage is what we can

maintain object oriented data means what

for example here it is the struct

keyword that denotes what we are going

to start a structure structure name and

structure members they are called and

here to work with this structure I'm

going to declare some variables like

this suppose S10 now what happens here

S1 S2 S10 are called structure

variables generally variables are stored

in stack that's why here just assume it

is the stack now it is the stack and

first structure variable S1 now this S1

require how many byes okay here ID is

the integer that's why it takes two

bytes and here S6 is six integers that's

why it require 12 btes now I'm going to

reduce this now three s of 3 now what

happened ID requires 2 bytes s of Three

6 bytes and name 20 that's why memory is

allocated like

this now it is a s one first two bytes

are allocated for ID now two

byes and later s of three is there now

what happen watch it here structure name

is what structure variable name S1 and

array name is yes now yes and three

integers memory allocated that means

total 6 bytes memory allocated and Base

address passord to yes and now

later name also there now now it is the

name and it requires total 20 bytes

that's why total this structure size is

28 bytes now the compiler is indicating

28 bytes required for this

structure okay like this the memory is

allocated for structure variables now to

access these members we are using S1 do

ID S1 do name S1 do subjects okay it is

a common thing and now structure allows

to store the data like this suppose it

is S1 structure data means here we are

able to store one student data one

student Marks One student name that

means all they are related to one

student here that one student is called

one object next S2 also same that S2

allows to store

second student data S3 S4 like this now

it is called object oriented that's why

structures are the

foundation now what is the problem with

structure okay now we are going to

discuss what is the disadvantage in

structure now the problem is in C

language in C language the structure

data is by default

public it is the main problem

that means what okay now the structure

data is accessible from anywhere in our

program through the structure variables

that means outside members other members

or member functions or functions anybody

can access the structure data that's why

structure data is not protected because

of structure data is public by default

structure members are public

okay now to avoid this problem they have

introduced the concept of class and one

more thing is in C++ also we are having

structures okay here the point is

actually we have discussed about C

language structure and actually our

topic is what C++ now we are having

structures in C++ also now what is the

difference okay in C language inside the

structure we are able to declare only

the variables which are called structure

members in C language inside the

structure we are able to declare only

the structure members means only the

variables only but in

C++ in C++ structure we can

declare strcture members and member

function

also it is the major

difference okay now we are able to

declare data members generally called

Data members okay which are also called

structure members and now C++ structure

allows to declare both the variables and

function inside the structure but C

structure never allows this kind of

Declaration it is the only difference

between C structure and C ++ structure

but here one point we have to discuss

that is what in C++ also the structure

data is public that means anybody can

access from anywhere that's why

structure data is not secured that's why

to avoid this problem okay they have

introduced class Concept in

C++ now in C++ how how the data is

secured that's why they have designed

the class like this the class data is

divided into private protected public

members in see there is no private

public protected only public is there

and in C++ structure also we are having

private protected public but here one

important thing is there what is that

thing okay here in C++ structure okay we

are are not able to Define complex

programs with the C++ structures we are

not able to design complex programs

means big project works but it is

possible with the class concept because

of classes allows the concept of

inheritance okay first observe it

carefully here one point is there

structure is available in C language and

all the structure members are public by

default in C language and C structure

allows only the variables inside the

structure which are called structure

members okay and now it is not protected

structure data is not protected now in

C++ what happened in C++ also they're

using structures but the only one

difference is okay here they have

introduced member functions they have

introduced member functions with private

public protected

declarations but the problem with the

C++ structure is they're not able to use

for Designing the big applications here

big application means project works it

is the major problem and here also

problem is data is public everybody can

access that's why to avoid this problem

in C++ which concept is introduced

class now what is a class class also

extension of C structure now according

to this explanation class is the

extension of C structure now the

difference is what in C++ there is a

rule what it is means the private data

of a class should be accessed with

member functions of same class it is the

main thing in previous discussion what

happens structure data is structure data

is accessed by okay structure members

and outers also in C++ structure the

structure data is accessed by structure

members outers in C structure also the

data is accessed by outers that's why C

and C++ structure data is not secured

that's why they have introduced one

formula what it is okay in C++ the price

prate data should be accessed only with

the member functions of same class now

what is called member functions okay

here the functions that are declared

inside the class are called member

functions that means outers are not

allowed okay certain rules and the

regulations are there that means certain

limitations are also there what it is

friend function pointers by using friend

functions and pointers we can access the

class data also but actually the rule is

what means the private data should have

to access with member functions of same

class okay that's why they have designed

class now how the class is working see

this suppose it is the

class suppose student class it is now

inside the student class I'm going to

use either

private or public or

protected later I'm going to declare the

data

members and member

functions now class and

semicolon see this here it is looking to

be the C++ structure now both are having

same but the only difference is here

private public protected declared now

and data members member function

declared here also we can but the major

difference is they are used in

inheritance concept means class allows

the concept of inheritance but structure

never allows the concept of inheritance

and now what happens since based on this

I'm going to give one small example

Suppose there is a class called

St and here I'm not going to mention

private or public automatically all the

members will become private and here in

C++ structure by default all the members

are public it is another important

difference between structure and class

that's why by default structure data is

public by default class data is private

now when it is private what happens

suppose private I'm going to declare

like this

now it is called visibility label or

access specifier later in

ID next character name of 20 next in

this section I'm going to write one

function public or private what it may

be then suppose public wi get now inside

this function I can access the ID and

name using C out and CNR directory what

it may be here ID and name are declared

inside the class under private and get

is declared in public section and inside

the get we are asking ID and name okay

here I'm going to access the ID and name

that means here where we are accessing

the data members that is inside the

member function here get is called

member function why because it is right

now member of this class that's why the

functions that are

declared inside a class are called

member functions and with the help of

member functions only we can access the

private data of a class that means now

this data is not accessible from outside

the class which is called Data hiding

which is called Data hiding okay

next it is available to only the member

functions and this concept is called

Data hiding that's why the key factor of

data hiding is achieved with private

declarations when the members are

private they can be accessed with the

member functions okay I'm giving small

example generally we are using mobile

phones now suppose one mobile phone is

there right now it is placed in my

pocket and

who is going to use this one me and my

family members okay and here there is no

permission required because of they my

family members my members and when it is

placed on the road when it is placed

outside now it is able to access by any

person because of now it is called

public okay when it is inside the pocket

it is private member that's why private

means restrict

only authorized people can access when

it is on the road means public anybody

can access now the structure data is

public and class data is private that

means outers are not able to access

without permission that's why user is

able to design secured applications

using C++ class concept okay that's why

class allows to

declare okay class allows to declare

both of the variables and functions at

one place now the variables are called

Data members and functions are called

member function that's why here what is

happening the data and functions both

are

associated okay and now according to

this explanation class is the

combination of data members and member

functions that's why simply class is

collection of of members that's why here

the main point is main point is classes

collection of members what kind of

members data members and member

functions now both are associated

together okay into a single unit called

class which is called

encapsulation that's why encapsulation

is the process of binding the data and

Associated functions together

into a single unit called

class this one is possible with class

that's why class provides the major

concept of data bind hiding data hiding

means insulating the data from external

access means outers are not allowed only

members can access it is called Data

hiding second one encapsulation means

Binding off or Tiding the data members

and member functions into a single unit

called class it is nothing but

encapsulation future both are provided

with class concept that's why here class

is a user defined data type with a

complex data okay here class is a user

defined data type or it is the extension

of C structure next here from class we

have to declare the variables for

example here structure is there there

now to access the structure members we

should have to declare the structure

variables we should have to declare the

structure variables then only the memory

is allocated in stack similar to that in

class also in class also to access the

data Members First memory have to be

allocated and when it is allocated means

when the objects are created now what is

called object here we are calling there

are structure variables here they are

called class variables here called class

variables and the class variables are

called objects that's why object meaning

is what it is a variable of type class

for example I'm going to declare like

this void

main now St s here s is

called object now it is nothing but a

variable of type class that's why object

meaning is class variables now the

memory also allocated for s means now s

is having data members now for data

members the memory is allocated that's

why to access the class members we have

to declare the objects later to access

the object members see this I'm going to

access like this for example s do get

now it is called

calling it is called calling that's why

to call or to access the class data

members or functions we should have to

use the object name now here this object

is Created from this class that's why

class is a

blueprint class is a blueprint to

construct the objects okay that's Sol I

said class is a user defined data now

I'm saying class is a blueprint here

blueprint means what original copy

blueprint means original copy to

construct the gerox copies gerox means

what instances now instances mean what

copies now the copies are nothing but

objects that's why to create the objects

we need the class that's why class is a

blueprint and object is the instance of

a class that's why another definition

already we have discussed what object is

a class variable now I am saying object

is the instance of a class and another

definition okay class okay here one

small point is there already have given

two explanations about object and the

next explanation is object is the

physical representation of a class

object is the physical IAL

representation of a class that means

what okay here I said class is the

blueprint means original copy and

objects are the gerox okay here the

point is when the object is created then

only memory allocated that means

according to this example class never

takes the memory means when class is

created memory not allocated when

objects are created then only memory

allocated means which requires the

memory means object that's why object is

the physical and class is The

Logical okay it is a major point now it

is nothing but what is a class what is

an object okay in this session I'm going

to cover the remaining whoops features

thank you for

[Music]

watching

[Music]