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.
00:17 To record this tutorial, I am using:
00:20 Ubuntu OS version 11.10 and
00:24 g++ compiler version 4.6.1
00:29 In multiple inheritance, derived class inherits from more than one base class.
00:36 Now, we will see an example on multiple inheritance.
00:40 I have already typed the code on the editor.
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.
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.
01:07 This is the base class.
01:09 In this, we have roll_no as integer variable and name as character variable.
01:16 These are declared as protected.
01:19 Then we have another class exam_inherit.
01:24 This is also a base class.
01:26 Hence we have two base classes 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.
01:50 This inherits the base classesclass "student"' and class "exam_inherit".
01:56 In this, we have avg as integer variable declared as private.
02:02 Then we have functions:
02:04 input()
02:05 display()
02:06 average()
02:07 input_exam()
02:08 and display_exam() as public functions.
02:11 In this, we have total as integer variable declared as public.
02:17 Then, we use input() function to accept the roll_no and name of the student.
02:24 In display() function, we display the roll_no and name of the student.
02:28 Here, we have function input_exam().
02:31 In this, we accept the marks of three subjects as sub1, sub2 and sub3.
02:37 Then in display_exam() function, we calculate the total of three subjects

and print the total.

02:44 And in function average(), we calculate the average.
02:48 This is our main() function.
02:51 In this, we create an object of class grade which is the derived class as gd.
02:57 Then we call all the above functions.
03:01 This is our return statement.
03:03 Now, let us execute the program.
03:05 Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
03:14 To compile, type: g++ space multiple dot cpp space hyphen o space mult. Press Enter.
03:24 Type: dot slash mult. Press Enter.
03:29 Here we see, Enter Roll no.:
03:32 I will enter as 3.
03:34 Enter Name:
03:36 I will enter as Pratham.
03:39 Enter marks of subject1
03:41 I will give as 67.
03:43 subject2 as 78 and.
03:46 subject3 as 84.
03:48 The output is displayed as:
03:51 Roll no is: 3
03:52 Name is: Pratham
03:53 Total is: 229
03:55 Average is: 76.
03:58 This was multiple inheritance.
04:00 Now, we will see hierarchical inheritance.
04:03 Come back to our program.
04:05 In hierarchical inheritance, multiple derived classes inherit from one base class.
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.
04:40 Then name as character variable.
04:43 These are declared protected.
04:46 Here, we have another class 'show'.
04:49 This is the derived class.
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.
05:07 In function display(), we display the roll_no and name of the student.
05:11 Then we have another derived class as class exam.
05:15 This also inherits class student.
05:19 You can see that there are two derived classes- class exam and class show.
05:26 Both the classes inherit the class "student".
05:30 In class exam, we have two functions as input_exam() and total_marks() declared as public.
05:38 Here, we access the function input_exam().
05:41 It accepts the marks of three subjects- sub1, sub2 and sub3.
05:46 Then we have total_marks() function.
05:49 It calculates the total of three subjects and prints the total.
05:53 This is our main() function.
05:56 In this, we create objects of three classes as st, sw and em.
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.
06:21 Let me clear the prompt.
06:24 Let us compile, type: g++ space hierarchical dot cpp space hyphen o space hier
06:36 Press Enter.
06:37 Type: dot slash hier
06:41 Press Enter.
06:43 Enter Roll no.:
06:44 I will give as 4.
06:46 Enter Name:
06:47 I will give as Ashwini.
06:50 Enter marks of subject1
06:52 I will give as 87.
06:54 subject2 as 67 and subject3 as 97.
07:00 The output is displayed as:
07:02 Roll no is: 4
07:04 Name is: Ashwini and
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.
07:14 In this tutorial, we learnt-
07:16 Multiple Inheritance and
07:18 Hierarchical Inheritance.
07:20 As an assignment:
07:21 Create a class area and perimeter.
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.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14