Advanced-C++/C2/Inheritance/English-timed

Time	Narration
00:01	Welcome to the spoken tutorial on Inheritance in C++.
00:06	In this tutorial, we will learn:
00:09	* Inheritance
00:10	* Types of inheritance.
00:12	We will do this with the help of examples.
00:16	To record this tutorial, I am using:
00:19	* Ubuntu OS version 11.10
00:24	* g++ compiler version 4.6.1
00:28	Let us start with an introduction to Inheritance.
00:32	When one object acquires the property of another, it is called as inheritance.
00:38	It is the process of reusing the existing class without modifying them.
00:44	Types of Inheritance-
00:45	* Single level inheritance
00:48	* Multiple level inheritance
00:50	* Hierarchical Inheritance
00:52	* Multilevel inheritance and
00:55	* Hybrid Inheritance.
00:57	First, let us know about the base class and the derived class.
01:02	The base class has its own properties and functionality.
01:06	It is also called as parent class.
01:09	It has the common qualities that all the objects can inherit.
01:14	The derived class is the child class.
01:18	Derived class inherits the properties and functionality of the base class.
01:23	Let us see what is single level inheritance.
01:27	In single level inheritance only one base class and one derived class is needed.
01:34	Multiple inheritance-
01:37	In multiple inheritance, derived class inherits from more than one base class.
01:44	Hierarchical Inheritance-
01:47	In Hierarchical Inheritance, multiple derived classes inherit from one base class.
01:55	Multilevel inheritance-
01:57	In Multilevel inheritance, the subclass acts as the base class for other classes.
02:05	And Hybrid inheritance-
02:08	In hybrid inheritance, more than one form of inheritance is combined.
02:14	Now let us see an example on single level inheritance.
02:18	I have already typed the code on the editor.
02:21	I will explain it.
02:23	Note that our file name is exam_inherit.cpp.
02:28	The example involves to display the name, roll no and marks of the student.
02:35	This is our header file as iostream.
02:38	Here, we are using the std namespace.
02:42	Here, we have class student.
02:44	Then we have an integer variable roll_no and character array name, as private members of class student.
02:53	Function input() and function display() are the public functions of class student.
02:59	Here we are using the input() function to accept the roll no. and name of the student.
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.
03:16	This is the derived class.
03:18	It inherits the function and data of class student.
03:23	Then we have declared sub1, sub2, sub3 and total
03:28	as private variables of class exam_inherit.
03:33	Here we have input_exam() and display_exam() as public functions.
03:41	Here we close the class exam_inherit.
03:44	Now, we are using input_exam() function to accept the marks of three subjects.
03:52	Here, we are using display_exam() function to calculate the total of three subjects.
03:59	Then we print a total.
04:01	This is our main() function.
04:03	Here we create an object of class exam_inherit as ex.
04:10	Then we call all the functions using the object ex.
04:15	And this is our return statement.
04:18	Let us execute the program.
04:20	Open the terminal window by pressing Ctrl, Alt and T keys simultaneously, on your keyboard.
04:30	To compile, type:
04:31	g++ (space) exam_inherit.cpp (space)-o (space) exam.
04:41	Press Enter.
04:42	Type:
04:43	./ (dot slash) exam. Press Enter.
04:46	Here it is displayed as:
04:47	Enter Roll no.:
04:49	I will give as 1.
04:51	Enter Name:
04:52	I will enter as Arya.
04:55	Enter marks of subject1
04:57	I will give as 60,
05:00	subject 2 as 70
05:02	and subjec 3 as 80.
05:06	The output is displayed as:
05:08	Roll no is: 1
05:09	Name is: Arya and
05:11	Total is: 210.
05:13	Now, we will see multilevel inheritance in the same example.
05:18	I have already typed the code.
05:20	Let's switch back to our editor.
05:22	Note that our file name is multilevel.cpp.
05:28	Here, we have declared the variable total.
05:32	as public variable of class exam_inherit.
05:38	This is because the private members are not accessed by the derived class.
05:44	Here we have another class as grade.
05:49	This inherits the class exam_inherit.
05:53	Class grade is the derived class
05:56	and class exam_inherit is the base class for class grade.
06:02	All the functions and data of class exam_inherit will be inherited to class grade.
06:11	Here, we have declared avg as private member of class grade
06:17	and function average() as public function.
06:21	Then we close the class.
06:23	Here we use the average() function to calculate the average.
06:27	Then we print the average.
06:30	Inside the main function, we create an object of class grade as gd.
06:36	Then we call all the functions using the object gd.
06:40	gd.input()
06:42	input_exam()
06:44	display()
06:45	display_exam()
06:46	and the average() function.
06:49	And this is our return statement.
06:52	Now you can see that class grade is the derived class.
06:56	and exam_inherit is the base class for class grade.
07:01	And here class exam_inherit is the derived class.
07:06	And class student is the base class for class exam_inherit.
07:12	Let us execute the program.
07:14	Come back to our terminal.
07:17	To compile, type:
07:18	g++ (space) multilevel.cpp (space) -o (space) mul
07:26	Press Enter.
07:27	Type ./mul
07:30	Press Enter.
07:32	Here we see, Enter Roll no.:
07:34	I will enter as 2.
07:36	Enter Name:
07:38	I will enter as Pratham.
07:41	Enter marks of subject1
07:43	I will give as 65,
07:46	subject2 as 67 and
07:48	subject3 as 82.
07:52	The output is displayed as:
07:54	Roll no is: 2
07:56	Name is: Pratham
07:57	Total is: 214 and
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.
08:08	In this tutorial, we learnt:
08:10	* Inheritance and
08:11	* Types of inheritance.
08:14	As an assignment-
08:15	write a program to create a class Shape.
08:18	Then create two functions of the class as Area and Perimeter.
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:
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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.

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PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14