Difference between revisions of "Advanced-C++/C2/Polymorphism/English-timed"

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|| '''Time'''
 
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|| '''Narration'''
 
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|* '''Polymorphism'''
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|'''Polymorphism''' '''Virtual Function.'''
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|* '''Virtual Function.'''
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| To record this tutorial, I am using:
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|To record this tutorial, I am using:
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* '''Ubuntu OS '''version '''11.10'''
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'''Ubuntu OS '''version '''11.10'''
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* '''g++ compiler '''version '''4.6.1'''
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'''g++ compiler '''version '''4.6.1'''
  
 
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|  00:27
 
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|  Let us start with the introduction to '''polymorphism.'''
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|  Let us start with an introduction to '''polymorphism.'''
  
 
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| '''Virtual''' function is the member function of a '''class'''.  
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| '''Virtual''' function is the '''member function''' of a '''class'''.  
  
 
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|  Now let us see an example on '''virtual functions.'''
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|  Now, let us see an example on '''virtual functions.'''
  
 
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| In this program:
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| In this program,we will calculate the area of a rectangle, parallelogram and triangle.
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| We will calculate the area of a rectangle, parallelogram and triangle.
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| Here we are using '''std namespace.'''
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| Here we are using the '''std namespace.'''
  
 
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| Then we have a '''class parallelogram'''.  
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| Then, we have a '''class Parallelogram'''.  
  
 
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| In this, we have declared''' integer variables''' as '''width,height''' and '''ar.'''
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| In this, we have declared''' integer variables''' as '''width, height''' and '''ar.'''
  
 
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| Here we have passed two '''arguments''' as '''a ''' and''' b.'''
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| Here, we have passed two '''arguments''' as '''a ''' and''' b.'''
  
 
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|01:55
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| Then we access the '''protected''' members using the '''public members'''.
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| Then we access the '''protected members''' using the '''public members'''.
  
 
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| This is our '''virtual function "area".'''
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|This is our '''virtual function area()'''.
  
 
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|   Then we have '''class''' '''Rectangle''' as a '''derived class.'''
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|Then we have '''class''' '''Rectangle''' as a '''derived class.'''
  
 
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| It inherits the properties of '''base class''' '''parallelogram'''.
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| It inherits the properties of '''base class''' '''Parallelogram'''.
  
 
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|  Here we '''override''' the function '''area'''.
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|  Here we '''override''' the function '''area()'''.
  
 
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| This also inherits the properties of the '''base class''' '''parallelogram'''.
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| This also inherits the properties of the '''base class''' '''Parallelogram'''.
  
 
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| Here again we '''override''' the function '''area'''.
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| Here again we '''override''' the function '''area()'''.
 
   
 
   
 
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|  Then we calculate the area of the triangle.
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|  Then we calculate the area of the triangle
  
 
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| And '''print''' the '''value'''.
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| and '''print''' the '''value'''.
  
 
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|  Here we create an '''object'''of '''class parallelogram''' as '''p.'''
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|  Here we create an '''object'''of '''class Parallelogram''' as '''p.'''
  
 
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| Here, '''Parallel''' is assigned to the address of '''p.'''
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|Here, '''parallel''' is assigned to the address of '''p.'''
  
 
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| Then we call function '''area().'''
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| Then we call the function '''area().'''
  
 
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|  Here, '''Parallel''' is assigned to the address of '''rect'''.
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|  Here, '''parallel''' is assigned to the address of '''rect'''.
  
 
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|  And, at last we assign '''Parallel''' to the address of '''Triangle '''
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|  And, at last we assign '''parallel''' to the address of '''Triangle '''
  
 
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| Open the '''terminal window''' by pressing '''Ctrl, Alt''' and '''T '''keys simultaneously on your keyboard.
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|Open the '''terminal window''' by pressing '''Ctrl, Alt''' and '''T '''keys simultaneously on your keyboard.
  
 
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|04:09
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| To compile, type:  
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|To compile, type: '''g++ space virtual.cpp space -o space vir''' press '''Enter'''.
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| '''g++ space virtual.cpp space -o space vir''' press '''Enter'''.
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| Let us summarize.
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| Let us summarize.In this tutorial, we learnt:
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|  04:37
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|  In this tutorial, we learnt:
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|  04:39
 
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|* '''Polymorphism'''
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|'''Polymorphism'''
  
 
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|* '''Virtual function''', example '''Virtual int area()'''.
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|'''Virtual function''', example '''Virtual int area()'''.
  
 
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|  As an assignment:  
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|  As an assignment:  Calculate the perimeter of rectangle, square and triangle.
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| 04:46
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|* Calculate the perimeter of rectangle, square and triangle.
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|* Create perimeter as a '''Virtual function.'''
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|Create perimeter as a '''Virtual function.'''
  
 
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|  04:54
 
|  04:54
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| Watch the video available at the link shown below.
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| Watch the video available at the link shown below.
  
 
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| For more details, please write to, contact@spoken-tutorial.org
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| For more details, please write to: contact@spoken-tutorial.org
  
 
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|05:37
 
|05:37
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|This is Ashwini Patil from IIT Bombay, signing off.
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|This is Ashwini Patil from IIT Bombay, signing off.Thank You for joining.  
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Thank You for joining.  
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|}
 
|}

Latest revision as of 14:59, 23 March 2017

Time Narration
00:02 Welcome to the spoken tutorial on Polymorphismin C++.
00:07 In this tutorial, we will learn:
00:10 Polymorphism Virtual Function.
00:13 We will do this through an example.
00:16 To record this tutorial, I am using:

Ubuntu OS version 11.10 g++ compiler version 4.6.1

00:27 Let us start with an introduction to polymorphism.
00:31 Polymorphism is the ability to take different forms.
00:36 It is the mechanism to use a function with same name in different ways.
00:42 Let us see virtual functions.
00:45 Virtual function is the member function of a class.
00:49 It can be overridden in its derived class.
00:53 It is declared with virtual keyword.
00:57 Virtual function call is resolved at run-time.
01:01 Now, let us see an example on virtual functions.
01:06 I have already written the code.
01:08 Let us go through it.
01:10 Note that our file name is virtual.cpp.
01:15 In this program,we will calculate the area of a rectangle, parallelogram and triangle.
01:22 This is our header file as iostream.
01:25 Here we are using the std namespace.
01:29 Then, we have a class Parallelogram.
01:33 This is the base class.
01:35 In this, we have declared integer variables as width, height and ar.
01:42 These are declared protected.
01:45 Then we have function set_values(), declared as public.
01:50 Here, we have passed two arguments as a and b.
01:55 Then we access the protected members using the public members.
02:00 This is our virtual function area().
02:04 Here we calculate the area of parallelogram.
02:07 Then we have class Rectangle as a derived class.
02:12 It inherits the properties of base class Parallelogram.
02:17 Here we override the function area().
02:21 Then we calculate the area of the rectangle.
02:23 And print the value.
02:25 Here we have another derived class as triangle.
02:29 This also inherits the properties of the base class Parallelogram.
02:35 Here again we override the function area().
02:39 Then we calculate the area of the triangle
02:41 and print the value.
02:43 This is our main() function.
02:46 Here we create an objectof class Parallelogram as p.
02:52 We can see here pointer parallel.
02:56 This is the pointer of class parallelogram.
03:00 This is called as Base pointer.
03:03 Pointer of base class can point to the object of the derived class.
03:08 Here we create objects of class Rectangle and Triangle.
03:14 Here, parallel is assigned to the address of p.
03:18 Then we pass arguments as 3 and 2.
03:23 Then we call the function area().
03:26 Here, parallel is assigned to the address of rect.
03:30 rect is the object of class Rectangle.
03:33 Again we pass arguments as 4 and 5.
03:37 And we call the function area().
03:40 And, at last we assign parallel to the address of Triangle
03:45 trgl.
03:47 This is the object of class Triangle.
03:51 Here, we pass arguments as 6 and 5
03:54 and call function area().
03:56 And this is our return statement.
03:59 Now, let us execute the program.
04:02 Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
04:09 To compile, type: g++ space virtual.cpp space -o space vir press Enter.
04:20 Type: ./vir press Enter.
04:24 You can see that the output is displayed as:
04:27 Area of parallelogram is 6
04:29 Area of rectangle is 20
04:31 and Area of triangle is 15.
04:34 Come back to our slides.
04:36 Let us summarize.In this tutorial, we learnt:
04:39 Polymorphism
04:41 Virtual function, example Virtual int area().
04:45 As an assignment: Calculate the perimeter of rectangle, square and triangle.
04:50 Create perimeter as a Virtual function.
04:54 Watch the video available at the link shown below.
04:57 It summarizes the Spoken-Tutorial project.
05:00 If you do not have good bandwidth, you can download and watch it.
05:04 The Spoken Tutorial Project team:
05:06 Conducts workshops using spoken tutorials.
05:09 Gives certificates to those who pass an Online test.
05:14 For more details, please write to: contact@spoken-tutorial.org
05:21 Spoken-Tutorial Project is a part of the "Talk to a Teacher" project.
05:25 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
05:32 More information on this mission is available at link shown below : http://spoken-tutorial.org/NMEICT-Intro
05:37 This is Ashwini Patil from IIT Bombay, signing off.Thank You for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14, Sneha

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