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

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|'''Time'''
| '''Narration'''

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

|-
| 00:07
| In this tutorial, we will learn:

|-
| 00:09
|* '''Multiple Inheritance'''

|-
| 00:11
|* '''Hierarchical Inheritance'''.

|-
| 00:13
|We will do this with the help of examples.

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| 00:17
| To record this tutorial, I am using:

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| 00:20
| '''Ubuntu OS '''version '''11.10''' and

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| 00:24
| '''g++ compiler '''version '''4.6.1'''

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| 00:29
| In '''multiple inheritance''', '''derived class''' inherits from more than one '''base class'''.

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|00:36
|Now, we will see an example on '''multiple inheritance'''.
 
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| 00:40
|I have already typed the '''code''' on the '''editor'''.

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| 00:42
|I will open it.

|-
| 00:45
|Note that our file name is '''multiple.cpp'''.

|-
| 00:49
| In this program, we will display the '''name, roll no, marks''' and '''average''' of the student.

|-
| 00:56
|Let me explain the code.

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| 00:59
| This is our '''header file''' as '''iostream'''.

|-
| 01:01
|  Here we are using the '''std namespace'''.

|- 
|01:05
|Then we have '''class student.'''

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| 01:07
|This is the '''base class.'''

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| 01:09
|In this, we have '''roll_no''' as '''integer variable''' and '''name '''as''' character variable'''.

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| 01:16
|These are declared as '''protected'''.

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| 01:19
|Then we have another '''class exam_inherit'''.

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| 01:24
|This is also a '''base class.'''

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| 01:26
| Hence we have two '''base class'''es here- ''' student''' and '''exam_inherit.'''

|-
| 01:32
|In this, we have 3 '''variables'''-  '''sub1, sub2''' and '''sub3''' as '''protected'''.

|-
| 01:38
|This is because '''protected variables''' can be accessed by '''derived class'''.

|-
| 01:44
|Now, here we have '''class "grade"''' which is the '''derived class'''.

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| 01:50
|This inherits the '''base classes''' – '''class "student"' and '''class "exam_inherit". '''

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| 01:56
| In this, we have '''avg''' as '''integer variable''' declared as '''private'''.

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| 02:02
| Then we have '''functions''':

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| 02:04
|'''input()'''

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| 02:05
|'''display()'''

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| 02:06
|'''average()'''

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| 02:07
|'''input_exam()'''

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| 02:08
|'''and display_exam()''' as '''public''' functions.

|-
| 02:11
|In this, we have '''total''' as '''integer variable''' declared as '''public'''.

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| 02:17
| Then, we use '''input()''' function to accept the '''roll_no''' and '''name''' of the student.

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| 02:24
| In''' display()''' function, we display the '''roll_no''' and '''name '''of the student.

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| 02:28
| Here, we have function '''input_exam().'''

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| 02:31
|In this, we accept the marks of three subjects as '''sub1, sub2''' and '''sub3.'''

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| 02:37
| Then in '''display_exam()''' function, we calculate the total of three subjects
and print the '''total'''.

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| 02:44
| And in function '''average()''', we calculate the average.

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|02:48
| This is our '''main()''' function.

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| 02:51
|In this, we create an''' object '''of '''class grade '''which is the''' derived class '''as''' gd'''.

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| 02:57
| Then we call all the above '''functions'''.

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| 03:01
| This is our '''return''' statement.

|-
| 03:03
|Now, let us '''execute''' the program.

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| 03:05
| Open the '''terminal window''' by pressing '''Ctrl, Alt''' and '''T '''keys simultaneously on your keyboard.

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| 03:14
| To compile, type: '''g++ space multiple dot cpp space  hyphen o space mult'''. Press '''Enter'''.

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| 03:24
|Type:''' dot slash mult'''. Press '''Enter'''.

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| 03:29
|Here we see, '''Enter Roll no.:'''

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| 03:32
|I will enter as '''3'''.

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| 03:34
|'''Enter Name:'''

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| 03:36
|I will enter as '''Pratham'''.

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| 03:39
|'''Enter marks of subject1'''

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| 03:41 
|I will give as '''67'''.

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| 03:43
|'''subject2''' as '''78''' and.

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| 03:46
|'''subject3''' as '''84'''.

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|03:48
|The '''output''' is displayed as: 

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| 03:51
|'''Roll no is: 3'''

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| 03:52
|'''Name is: Pratham'''

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| 03:53
|'''Total is: 229'''

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| 03:55
|'''Average is: 76'''.

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| 03:58
|This was '''multiple inheritance'''.

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| 04:00
|Now, we will see '''hierarchical inheritance'''.

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| 04:03
| Come back to our program.

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| 04:05
|In '''hierarchical inheritance,  multiple derived classes''' inherit from one '''base class'''.

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| 04:12
| Note that our 'file name' is '''hierarchical dot cpp'''.

|-
| 04:16
|I will explain the code now.

|-
| 04:19
| This is our '''header file''' as '''iostream.'''

|-
| 04:22
| Here we have used the '''std namespace'''.

|-
| 04:25
| Then, we have '''class  student''' which is the '''base class.'''

|-
| 04:29
|In this, we have '''roll_no''' as '''integer variable'''.

|-
| 04:34
|'''Sub1, sub2, sub3''' and '''total''' as '''integer variables'''.

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| 04:40
|Then '''name''' as '''character variable'''.

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| 04:43
|These are declared '''protected'''.

|-
| 04:46
| Here, we have another '''class 'show'.'''

|-
| 04:49
|This is the '''derived class'''.

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| 04:51
|It inherits the properties of''' class student.'''

|-
| 04:54
| In this, we have two '''functions: input()''' and '''display().'''

|-
| 04:59
|These are declared as '''public functions'''.

|-
|05:02
|In function '''input()''', we accept the '''roll_no''' and '''name''' of the student.

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| 05:07
| In function '''display()''', we display the '''roll_no''' and '''name''' of the student.

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| 05:11
| Then we have another '''derived class''' as class '''exam.'''

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| 05:15
|This also inherits '''class student.'''

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| 05:19
|You can see that there are two '''derived classes'''- '''class exam''' and '''class show.'''

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| 05:26
|Both the '''classes''' inherit the '''class "student".'''

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| 05:30
| In '''class exam''', we have two '''functions''' as '''input_exam()''' and '''total_marks()''' declared as '''public'''.

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| 05:38
| Here, we access the function '''input_exam()'''. 

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| 05:41
|It accepts the marks of three subjects- '''sub1, sub2''' and '''sub3'''.

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| 05:46
| Then we have ''' total_marks()''' function.

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| 05:49
|It calculates the total of three subjects and prints the '''total'''.

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| 05:53
| This is our '''main()''' function.

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| 05:56
|In this, we create '''objects''' of three '''classes''' as''' st, sw '''and''' em.'''

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| 06:03
| Then we call all the above '''functions''' using these objects.

'''sw.input();'''

'''em.input_exam();'''

'''sw.display();'''

'''em.total_marks();'''

|-
| 06:15
| And this is our '''return''' statement.

|-
| 06:17
|  Now, let us '''execute''' the program.

|-
| 06:19
|Come back to the '''terminal'''.

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| 06:21
| Let me clear the '''prompt'''.

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|  06:24
|Let us compile, type: '''g++ space  hierarchical dot cpp space  hyphen o space hier'''

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| 06:36
|Press '''Enter'''.

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| 06:37
|Type: '''dot slash hier'''

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| 06:41
|Press '''Enter'''.

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| 06:43
|'''Enter Roll no.:'''

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| 06:44
|I will give as '''4'''.

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| 06:46
|'''Enter Name:'''

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| 06:47
|I will give as '''Ashwini'''.

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| 06:50
|'''Enter marks of subject1'''

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| 06:52
|I will give as '''87'''.

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| 06:54
|'''subject2''' as '''67''' and '''subject3''' as '''97'''.

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| 07:00
| The '''output''' is displayed as:

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| 07:02
|'''Roll no is: 4'''

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| 07:04
|'''Name is: Ashwini '''and

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| 07:06
|'''Total is : 251'''

|-
| 07:07
|  This brings us to the end of this tutorial.

|-
| 07:10
|Come back to our '''slides'''.

|-
| 07:13
| Let us summarize.

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| 07:14
|In this tutorial, we learnt-

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| 07:16
|'''Multiple Inheritance''' and

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| 07:18
|'''Hierarchical Inheritance'''.

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| 07:20
|As an assignment: 

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| 07:21
|Create a '''class area''' and '''perimeter'''.

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| 07:25
|Find the area and perimeter of rectangle.

|-
| 07:29
|Watch the video available at the link shown below.

|-
| 07:32
|It summarizes the Spoken Tutorial project. 

|-
| 07:35
|If you do not have good bandwidth, you can download and watch it.

|-
| 07:40
|The Spoken Tutorial Project Team: 

|-
| 07:42
|Conducts workshops using spoken tutorials. 

|-
| 07:45
|Gives certificates to those who pass an online test. 

|-
| 07:49
|For more details, please write to:

|-
| 07:51
|contact@spoken-tutorial.org

|-
| 07:56
|Spoken Tutorial Project is a part of the "Talk to a Teacher" project.

|-
| 08:01
|It is supported by the National Mission on Education through ICT, MHRD, Government of India. 

|-
|08:07
|More information on this mission is available at the link shown below.
|-
|08:11
| This is Ashwini Patil from IIT Bombay, signing off. Thank You for joining. 

|}