View source for Advanced-C++/C2/Inheritance/English-timed

'''Title of script''': Objects and Classes in C++

'''Author: '''Ashwini Patil

'''Keywords: Inheritance, Single level Inheritance, Multilevel Inheritance, Multiple Inheritance, Video tutorial.'''



{| border=1
| '''Time'''
| '''Narration'''

|-
| 00:01
| Welcome to the spoken tutorial on '''Inheritance in C++.'''

|-
| 00:06
| In this tutorial we will learn,

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| 00:09
| '''Inheritance'''

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| 00:10
|'''Types of inheritance'''

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| 00:12
|We will do this with the help of examples.

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| 00:16
| To record this tutorial, I am using

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| 00:19
|'''Ubuntu OS '''version 11.10'''

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| 00:24
|'''g++ compiler '''v. 4.6.1'''

|-
| 00:28
|  Let us start with an Introduction to Inheritance

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| 00:32
|When one object acquires the property of another it is called as '''inheritance.'''

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| 00:38
|It is the process of reusing the existing class without modifying them.

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| 00:44
| '''Types of Inheritance'''

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| 00:45
|'''Single level inheritance'''

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| 00:48
|'''Multiple level inheritance'''

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| 00:50
|'''Hierarchical Inheritance '''

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| 00:52
|'''Multilevel inheritance'''

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| 00:55
|'''Hybrid Inheritance'''

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|00:57
| First let us know about the base class and the derived class.

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| 01:02
|The base class has its own properties and functionality.

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| 01:06
|It is also called as parent class.

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| 01:09
|It has the common qualities that all the objects can inherit.

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| 01:14
|The derived class is the child class.

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| 01:18
|Derived class inherits the properties and functionality of the base class.

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| 01:23
|Let us see what is single level inheritance.

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| 01:27
| In single level inheritance only one base class and one derived class is needed.

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| 01:34 
| Multiple inheritance

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| 01:37
|In multiple inheritance derived class inherits from more than one base class.

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|01:44
| '''Hierarchical Inheritance'''

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|01:47
| In Hierarchical Inheritance multiple derived classes inherits from one base class.

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| 01:55
| '''Multilevel inheritance'''

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| 01:57
| In Multilevel inheritance the subclass acts as the base class for other classes.

|-
|  02:05
| and Hybrid inheritance 

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|  02:08
|  In hybrid inheritance more than one form of inheritance is combined.

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|  02:14 
|  Now let us see an example on single level inheritance.

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| 02:18
|I have already typed the code on the editor.

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| 02:21
|I will explain it.

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| 02:23
|Note that our file name is  '''exam_inherit.cpp'''


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| 02:28
| The example involves to display the name, roll no and marks of the student. 

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| 02:35
| This is our header file as iostream

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| 02:38
|  Here we are using the '''std namespace'''

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| 02:42
|  Here we have class '''student.'''

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| 02:44
|  Then we have an integer variable '''roll_no''' and '''character array name.

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| 02:50
| As private members of '''class student'''.

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| 02:53
|  Function '''input '''and function''' display '''are the public functions of class student.


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| 02:59
| Here we are using the '''input''' function to accept the roll no. and name of the student.


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| 03:06
|  Then we have the '''display''' function to display the roll_no and name.


|-
| 03:11
|  Here we have another class as '''exam_inherit.'''

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| 03:16
|This is the derived class.

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| 03:18
|It inherits the function and data of class student.

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| 03:23
|  Then we have declared ''' sub1, sub2, sub3 and total.'''

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| 03:28
|As private variables of '''class exam_inherit.'''

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| 03:33
|  Here we have '''input_exam''' and '''display_exam as public functions.'''

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| 03:41
|Here we close the class '''exam_inherit.'''

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| 03:44
| Now we are using '''input_exam '''function to accept the marks of three''' '''subject.


|-
| 03:52
|  Here, we are using display_exam function to calculate the total of three subjects.

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| 03:59
|Then we print a total.

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| 04:01
|  This is our '''main function.'''

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| 04:03
|  Here we create an object of class exam_inherit as '''ex'''

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| 04:10
| | Then we call all the functions using the object '''ex'''

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| 04:15
| And this is our return statement.



|-
|  04:18
|  Let us execute the program

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| 04:20
| Open the '''terminal''' Window by pressing '''Ctrl, Alt and T '''keys simultaneously on your keyboard.

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| 04:30
|  To compile type,

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| 04:31
|'''g++ (space)exam_inherit.cpp (space)-o (space) exam'''

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| 04:41
| Press Enter.

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| 04:42
|Type

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| 04:43
|'''./exam''' Press Enter.

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| 04:46
|  Here it is displayed as,

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| 04:47
|'''Enter Roll no.:'''

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| 04:49
|'''I will give as 1'''

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| 04:51
|'''Enter Name:'''

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| 04:52
|'''I will enter as Arya'''

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| 04:55
|'''Enter marks of subject1'''

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| 04:57
|'''I will give as 60'''

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|  05:00
| '''subject 2 as 70'''

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|  05:02
| And '''subjec 3 as 80'''

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| 05:06
| The output is displayed as 

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| 05:08
|'''Roll no is: 1'''

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| 05:09
|'''Name is: Arya''' and,

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| 05:11
|'''Total is: 210'''

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| 05:13
|  Now we will see multilevel inheritance in the same example.

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| 05:18
| I have already typed the code.

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| 05:20
|Let's switch back to our ediotr.

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| 05:22
|Note that our filename is '''multilevel.cpp'''

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| 05:28
| Here we have declared the variable total.

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| 05:32
|As public variable of class exam_inherit.

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| 05:38
|This is because the private members are not accessed by the derived class.

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| 05:44
|  Here we have another class as '''grade.'''

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| 05:49
|This inherits the class '''exam_inherit.'''

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| 05:53
|Class '''grade''' is the derived class 

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| 05:56
| And class '''exam_inherit''' is the base class for class '''grade'''.

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| 06:02
| All the functions and data of class '''exam_inherit''' will be inherited to class '''grade'''.

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| 06:11
| Here we have declared '''avg''' as private member of class '''grade.''' 

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| 06:17
|And function '''average''' as public function.

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| 06:21
|Then we close the class.

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| 06:23
| Here we use the average function to calculate the average.

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| 06:27
|Then we print the average.

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| 06:30
| Inside the main function we create an object of class grade as '''gd.'''

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| 06:36
| Then we call all the functions using the object '''gd'''.

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| 06:40
|gd.input()

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| 06:42
|input_exam

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| 06:44
|display

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| 06:45
|display_exam

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| 06:46
|and the average function.

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| 06:49
|  And this is our return statement.

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|  06:52
|  Now you can see that class grade is the derived class.

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|  06:56
| And exam_inherit is the base class for class grade.

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| 07:01
| And here class exam_inherit is the derived class.

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| 07:06
| And class student is the base class for class exam_inherit.

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| 07:12
| Let us execute the program.

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| 07:14
| Come back to our terminal.

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| 07:17
| To compile type ,

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| 07:17
|'''g++ space multilevel.cpp space -o space mul'''

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| 07:26
|'''Press Enter'''

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| 07:27
|Type

'''./mul'''

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| 07:30
|'''Press Enter'''

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| 07:32
| Here we see,

'''Enter Roll no.:'''

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| 07:34
|I will enter as '''2'''

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| 07:36
|'''Enter Name:'''

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| 07:38
|I will enter as '''Pratham'''

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| 07:41
|'''Enter marks of subject1'''

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| 07:43
|I will give as '''65'''

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| 07:46
|'''subject2 as 67''' and,

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| 07:48
|'''subject3 as 82'''



|-
| 07:52
| The output is displayed as:

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| 07:54
|'''Roll no is: 2 '''

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| 07:56
|'''Name is: Pratham '''

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| 07:57
|'''Total is: 214 ''' and, 

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| 07:59
|'''Average is: 71''' 

|-
|  08:01
| This brings us to the end of this tutorial.

|-
|  08:05
|Let us move back to our slides.

|-
|  08:07
| Let us summarize

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|  08:08
|In this tutorial, we learnt,

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|  08:10
|Inheritance and,

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|  08:11
| Types of inheritance.

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| 08:14
|  As an assignment 


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| 08:15
| Write a program to Create a class Shape.

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| 08:18
| Then Create two functions of the class as Area and Perimeter.

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| 08:23
|Then find the area and perimeter of various shapes like square, rectangle and circle.

|-
|  08:31
| Watch the video available at the link shown below

|-
|  08:34
|It summarizes the Spoken Tutorial project 

|-
|  08:37
|If you do not have good bandwidth, you can download and watch it

|-
| 08:42
|  The Spoken Tutorial Project Team 

|-
| 08:44
|Conducts workshops using spoken tutorials 

|-
| 08:47
|Gives certificates to those who pass an online test 

|-
| 08:51
|For more details, please write to,

|-
| 08:53
|contact@spoken-tutorial.org

|-
| 08:58
| Spoken Tutorial Project is a part of the Talk to a Teacher project

|-
| 09:02
|It is supported by the National Mission on Education through ICT, MHRD, Government of India.

|-
| 09:09
|More information on this Mission is available at the link shown below

|-
| 09:13 
|  This is Ashwini Patil from IIT Bombay signing off

Thank You for joining. 

|}