Difference between revisions of "Advanced-C++/C2/Abstract-Class/English-timed"
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| − | |In this tutorial we will learn: | + | |In this tutorial, we will learn: |
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| 00:10 | | 00:10 | ||
| − | | | + | | Abstract Classes, Pure virtual function. |
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| 00:19 | | 00:19 | ||
| − | | | + | |'''Ubuntu OS '''version '''11.10''' |
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| 00:23 | | 00:23 | ||
| − | | | + | |'''g++ compiler '''version '''4.6.1''' |
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| 00:39 | | 00:39 | ||
| − | |We cannot create an instance of '''abstract class.''' | + | |We cannot create an '''instance''' of '''abstract class.''' |
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| 01:04 | | 01:04 | ||
| − | |Otherwise the '''compiler''' will give an error. | + | |Otherwise the '''compiler''' will give an '''error'''. |
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| 01:33 | | 01:33 | ||
| − | | Here we are using '''std namespace.''' | + | | Here we are using the '''std namespace.''' |
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| 02:35 | | 02:35 | ||
| − | | In this, again | + | | In this, again we override the function '''numbers()'''. |
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| 03:21 | | 03:21 | ||
| To compile, type: | | To compile, type: | ||
| − | + | '''g++ space abstract dot cpp space hyphen o space abs''' | |
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| 03:31 | | 03:31 | ||
| − | |press '''Enter'''. | + | |press '''Enter'''.Type: '''dot slash abs''' |
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| − | | It is displayed as '''Enter the numbers''' | + | | It is displayed as '''Enter the numbers'''. |
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| 03:42 | | 03:42 | ||
| − | |The output is displayed as '''Sum is 13'''. | + | |The '''output''' is displayed as '''Sum is 13'''. |
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| 03:52 | | 03:52 | ||
| − | |The output is displayed as ''' | + | |The '''output''' is displayed as '''diff is 5'''. |
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| − | | 03:56 | + | |03:56 |
| − | | This brings us to the end of this tutorial. | + | |This brings us to the end of this tutorial. |
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| 04:03 | | 04:03 | ||
| − | |In this tutorial, we learnt: | + | |In this tutorial, we learnt:'''Abstract class''' e.g. '''class abstractinterface'''. |
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| 04:14 | | 04:14 | ||
| − | | As an assignment- | + | | As an assignment- Create an '''abstract class''' '''student.''' |
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| 04:17 | | 04:17 | ||
| − | | | + | |Create a '''pure virtual function''' as '''Info'''. |
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| 04:20 | | 04:20 | ||
| − | | | + | |Accept the '''name''' and '''roll no''' of the student in the function. |
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| 04:25 | | 04:25 | ||
| − | | | + | |Create two '''derived class'''es '''marks''' and '''sports'''. |
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| 04:29 | | 04:29 | ||
| − | | | + | |In marks, accept marks of three subjects. |
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| 04:32 | | 04:32 | ||
| − | | | + | |In sports, enter marks scored in '''sports.''' |
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| 04:35 | | 04:35 | ||
| − | | | + | |Calculate the '''total marks.''' |
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| 04:38 | | 04:38 | ||
| − | | | + | |Then create another '''derived class''' as '''result.''' |
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| 04:41 | | 04:41 | ||
| − | | | + | |In this, display the''' name, roll-no''' and '''total marks''' of the student. |
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| 04:50 | | 04:50 | ||
| − | |It summarizes the Spoken Tutorial project. | + | |It summarizes the Spoken-Tutorial project. |
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| 04:58 | | 04:58 | ||
| − | | | + | |The Spoken Tutorial Project team: Conducts workshops using spoken tutorials. |
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| 05:07 | | 05:07 | ||
| − | |For more details, please write to | + | |For more details, please write to: contact@spoken-tutorial.org |
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| 05:14 | | 05:14 | ||
| − | | | + | |Spoken-Tutorial Project is a part of the "Talk to a Teacher" project. |
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| 05:25 | | 05:25 | ||
| − | |More information on this | + | |More information on this mission is available at the link shown below: http://spoken-tutorial.org/NMEICT-Intro |
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| 05:30 | | 05:30 | ||
| − | | | + | |This is Ashwini Patil from IIT Bombay, signing off.Thank You for watching. |
| − | Thank You for watching. | + | |
|} | |} | ||
Latest revision as of 15:04, 23 March 2017
| Time | Narration |
| 00:01 | Welcome to the spoken-tutorial on abstract class and pure virtual function in C++. |
| 00:08 | In this tutorial, we will learn: |
| 00:10 | Abstract Classes, Pure virtual function. |
| 00:13 | We will do this through an example. |
| 00:16 | To record this tutorial, I am using: |
| 00:19 | Ubuntu OS version 11.10 |
| 00:23 | g++ compiler version 4.6.1 |
| 00:27 | Let us start with an introduction to abstract class. |
| 00:31 | Abstract class is always a base class. |
| 00:35 | It contains at least one pure virtual function. |
| 00:39 | We cannot create an instance of abstract class. |
| 00:43 | Let us see pure virtual function. |
| 00:45 | A pure virtual function is a function with no body. |
| 00:49 | It is not defined in the base class. |
| 00:52 | It is declared as: |
| 00:54 | virtual void virtualfunname()=0; |
| 01:00 | A derived class must override the function. |
| 01:04 | Otherwise the compiler will give an error. |
| 01:07 | It is up to a derived class to implement the function. |
| 01:11 | Let us look at an example. |
| 01:13 | I have already typed the code on the editor. |
| 01:16 | I will open it. |
| 01:18 | Note that our file name is abstract.cpp. |
| 01:22 | This example involves addition and subtraction of two numbers. |
| 01:28 | Let us go through the code. |
| 01:30 | This is our header file as iostream. |
| 01:33 | Here we are using the std namespace. |
| 01:36 | This is declaration for a class named abstractinterface. |
| 01:41 | Then we have public specifier. |
| 01:44 | In this, we have declared a virtual function named numbers(). |
| 01:49 | It is initialized to 0. |
| 01:51 | Then we have a non-virtual function. |
| 01:55 | And two integer variables as 'a' and 'b'. |
| 01:59 | Here, we access the input function. |
| 02:01 | In this, we accept the numbers 'a' and 'b'. |
| 02:05 | This is a derived class named add. |
| 02:09 | It inherits the properties of the base class "abstractinterface". |
| 02:14 | Here we override the function numbers(). |
| 02:18 | In this, we perform addition of two numbers 'a'and 'b' |
| 02:21 | and store the result in integer variable "sum". |
| 02:25 | Then we print the result. |
| 02:27 | Here we have another derived class as sub. |
| 02:31 | This also inherits the base class "abstractinterface". |
| 02:35 | In this, again we override the function numbers(). |
| 02:39 | And here we calculate the difference of two numbers 'a' and 'b'. |
| 02:43 | Then we print the difference. |
| 02:45 | This is our main() function. |
| 02:48 | Here we create an object of class "add" as obj1. |
| 02:53 | Then we call both the functions input() and numbers() using the object obj1. |
| 02:59 | Then we create another object of class "sub" as obj2. |
| 03:04 | Again, we call the two functions using the object obj2. |
| 03:08 | And this is our 'return' statement. |
| 03:10 | Now let us execute the program. |
| 03:13 | Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard. |
| 03:21 | To compile, type:
g++ space abstract dot cpp space hyphen o space abs |
| 03:31 | press Enter.Type: dot slash abs |
| 03:34 | press Enter. |
| 03:36 | It is displayed as Enter the numbers. |
| 03:38 | I will enter as 9 and 4. |
| 03:42 | The output is displayed as Sum is 13. |
| 03:46 | Again we see Enter the numbers. |
| 03:49 | I will enter as 8 and 3. |
| 03:52 | The output is displayed as diff is 5. |
| 03:56 | This brings us to the end of this tutorial. |
| 03:59 | Come back to our slides. |
| 04:01 | Let us summarize. |
| 04:03 | In this tutorial, we learnt:Abstract class e.g. class abstractinterface. |
| 04:09 | Pure virtual function e.g. virtual void numbers()=0; |
| 04:14 | As an assignment- Create an abstract class student. |
| 04:17 | Create a pure virtual function as Info. |
| 04:20 | Accept the name and roll no of the student in the function. |
| 04:25 | Create two derived classes marks and sports. |
| 04:29 | In marks, accept marks of three subjects. |
| 04:32 | In sports, enter marks scored in sports. |
| 04:35 | Calculate the total marks. |
| 04:38 | Then create another derived class as result. |
| 04:41 | In this, display the name, roll-no and total marks of the student. |
| 04:47 | Watch the video available at the link shown below. |
| 04:50 | It summarizes the Spoken-Tutorial project. |
| 04:53 | If you do not have good bandwidth, you can download and watch it. |
| 04:58 | The Spoken Tutorial Project team: Conducts workshops using spoken tutorials. |
| 05:03 | Gives certificates to those who pass an online test. |
| 05:07 | For more details, please write to: contact@spoken-tutorial.org |
| 05:14 | Spoken-Tutorial Project is a part of the "Talk to a Teacher" project. |
| 05:18 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
| 05:25 | More information on this mission is available at the link shown below: http://spoken-tutorial.org/NMEICT-Intro |
| 05:30 | This is Ashwini Patil from IIT Bombay, signing off.Thank You for watching. |
