Difference between revisions of "Advanced-C++/C2/Classes-And-Objects/English-timed"

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|  Welcome to the spoken tutorial on '''Classes '''and''' Objects''' in '''C++.'''
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|  Welcome to the spoken tutorial on '''Classes and Objects''' in '''C++.'''
  
 
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| 00:07
 
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| In this tutorial we will learn,
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| In this tutorial, we will learn:
  
 
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| 00:09
 
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| '''Classes.'''
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|* '''Classes'''
  
 
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| 00:11
 
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| '''Objects.'''
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|* '''Objects'''
  
 
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| 00:12
 
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| '''Encapsulation.''' and
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|* '''Encapsulation''' and
  
 
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| 00:14
 
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| '''Data abstraction.'''
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|* '''Data abstraction.'''
  
 
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| To record this tutorial, I am using
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| To record this tutorial, I am using:
  
 
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| 00:23
 
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|'''Ubuntu OS '''version 11.10
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|*'''Ubuntu OS '''version '''11.10'''
  
 
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|'''g++ compiler '''version 4.6.1
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|*'''g++ compiler '''version '''4.6.1'''
  
 
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|  00:32
 
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| Let us start with the introduction to classes.
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| Let us start with the introduction to '''class'''es.
  
 
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|'''Class''' is created using a '''keyword class'''
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|'''Class''' is created using a '''keyword class'''.
  
 
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| Class links the '''code''' and '''data'''.
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| '''Class''' links the '''code''' and '''data'''.
  
 
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| The '''data''' and '''functions''' of the class are called as members of the class.
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| The '''data''' and '''functions''' of the '''class''' are called as members of the class.
  
 
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| 00:51
 
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|  Let us move on to objects.
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|  Let us move on to '''object'''s.
  
 
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|'''Behavior''' is defined through member functions called '''methods'''.
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|'''behavior''' is defined through member functions called '''methods'''.
  
 
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| Now let us see the syntax for a class
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| Now let us see the '''syntax''' for a class.
  
 
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|And here we have defined the Data members and the member functions as public, private and protected.
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|And here we have defined the data members and the member functions as '''public, private''' and '''protected'''.
  
 
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Revision as of 07:45, 27 June 2015

Time Narration
00:01 Welcome to the spoken tutorial on Classes and Objects in C++.
00:07 In this tutorial, we will learn:
00:09 * Classes
00:11 * Objects
00:12 * Encapsulation and
00:14 * Data abstraction.
00:16 We will do this with the help of an example.
00:20 To record this tutorial, I am using:
00:23 *Ubuntu OS version 11.10
00:28 *g++ compiler version 4.6.1
00:32 Let us start with the introduction to classes.
00:36 Class is created using a keyword class.
00:39 It holds data and functions.
00:42 Class links the code and data.
00:45 The data and functions of the class are called as members of the class.
00:51 Let us move on to objects.
00:53 Objects are variables.
00:55 They are the copy of a class.
00:58 Each of them has properties and behavior.
01:01 Properties are defined through data elements and
01:06 behavior is defined through member functions called methods.
01:10 Now let us see the syntax for a class.
01:14 Here, class is a keyword used to define a class.
01:18 Class-name is the name of the class.
01:21 Public, private and protected are the access specifier.
01:26 And here we have defined the data members and the member functions as public, private and protected.
01:34 This is how we close the class.
01:37 Now let us see an example
01:39 I have already typed the code on the editor.
01:42 I will open it.
01:44 Note that our filename is class hyphen obj dot cpp
01:50 In this example we will calculate the area of a square using class.
01:56 Let me explain the code now.
01:58 This is our header file as iostream.
02:02 Here we are using the std namespace
02:06 This is declaration for a class named square.
02:10 Here I have not declared any access specifier.
02:14 So by default it is private.
02:17 Hence variable x is a private member of class square.
02:22 This is the public specifier
02:25 Function area is a public function.
02:28 And this is how we close the class.
02:31 Now let us move back to our slides to know more about the access specifiers.
02:36 Public specifier
02:39 The public specifier allows the data to be accessed outside the class.
02:44 A public member can be used anywhere in the program.
02:49 Private specifier
02:51 The members declared as private cannot be used or accessed outside the class.
02:57 Private' members can be used only by the members of the class.
03:03 Protected specifier
03:05 Protected members cannot be accessed from outside the class.
03:10 They can be accessed by a derived class.
03:13 Let us move back to our program.
03:16 Here in this statement we have the class name
03:21 The scope resolution operator and the function name.
03:25 We must use this operator.
03:27 It specifies that function area is not a global function.
03:33 It is a member function of class square.
03:36 Here we have passed an argument as int a.
03:40 Now let us switch back to the slides to know more about the scope resolution operator.
03:46 It is used to access the hidden data.
03:49 To access the variable or function with the same name we use the scope resolution operator ::.
03:56 Suppose the local variable and the global variable have same name.
04:01 The local variable gets the priority.
04:05 We can access the global variable using ::(scope resolution operator.)
04:10 Now switch to our program.
04:12 Here the value of a is stored in x
04:17 Then we return the area of the square
04:20 Here x is a private member.
04:22 To access the private parameter we used the public member a.
04:27 private members are always hidden.
04:30 This is our main function.
04:33 Here, sqr is the object of class square.
04:37 This is how we create an object
04:40 class-name followed by the object-name
04:43 Here we call the function area using the object sqr and a .(dot) operator.
04:50 Then we pass an argument as 4.
04:53 we set the value of x as 4.
04:57 This is our return statement
04:59 Now Click on Save
05:00 Let us execute the program.
05:03 Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
05:11 To compile type g++ space class hyphen obj dot cpp space hyphen o space class
05:20 Press Enter
05:22 Type./class(dot slash class)
05:24 Press Enter
05:25 The output is displayed as:
05:28 Area of the square is 16
05:30 Now let us move back to our program.
05:35 So far now we have seen,
05:37 The data and functions combined together in a class.
05:41 Class is a single unit.
05:44 In which the data and the function using them is grouped.
05:49 This mechanism is called as Encapsulation.
05:53 Then we have seen class with the private and public members.
05:59 The private data is hidden.
06:02 It cannot be accessed outside the class.
06:05 This mechanism is called as Data abstraction.
06:09 The interface is seen but the implementation is hidden.
06:14 This brings us to the end of this tutorial.
06:17 Let us move back to our slides.
06:19 Let us summarize
06:20 In this tutorial we have learnt,
06:23 Encapsulation
06:24 Data Abstraction
06:25 Private members
06:27 int x;
06:29 Public functions
06:30 int area(int);
06:32 Classes
06:33 class square
06:35 To create object
06:37 square sqr;
06:39 To call a function using object sqr dot area();
06:43 As an assignment
06:44 write a program to find the perimeter of a given circle.
06:49 Watch the video available at the link shown below
06:52 It summarizes the Spoken Tutorial project
06:55 If you do not have good bandwidth, you can download and watch it
07:00 The Spoken Tutorial Project Team
07:02 Conducts workshops using spoken tutorials
07:05 Gives certificates to those who pass an online test
07:09 contact@spoken-tutorial.org
07:16 Spoken Tutorial Project is a part of the Talk to a Teacher project
07:20 It is supported by the National Mission on Education through ICT, MHRD, Government of India
07:26 More information on this Mission is available at the link shown below
07:31 This is Ashwini Patil from IIT Bombay signing off

Thank You for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14

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