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

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Title of script: Objects and Classes in C++

Author: Ashwini Patil

Keywords: Inheritance, Single level Inheritance, Multilevel Inheritance, Multiple Inheritance, Video tutorial.


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 v. 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
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 inherits 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.
02:50 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 subject.


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 ./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
05:00 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 ediotr.
05:22 Note that our filename 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 ,
07:17 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
08:44 Conducts workshops using spoken tutorials
08:47 Gives certificates to those who pass an online test
08:51 For more details, please write to,
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.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14