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

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Revision as of 22:50, 27 June 2015

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:
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