Advanced-C++/C2/Static-Members/English-timed

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Time Narration
00:01 Welcome to the spoken tutorial on static members in C++.
00:06 In this tutorial, we will learn:
00:09 Static keyword. Static variable
00:12 Static function.
00:14 We will do this through an example.
00:17 To record this tutorial, I am using:
00:20 Ubuntu OS version 11.10
00:24 g++ compiler version 4.6.1
00:29 Let us start with an introduction to static.
00:33 Static variables are initialized to zero before the first object is created.
00:39 Only one copy of the static variable exists for the whole program.
00:44 All the objects will share that variable.
00:47 It will remain in the memory till the end of the program.
00:52 Static functions-
00:54 A static function may be called by itself without depending on any object.
01:00 To access a static function, we use-
01:03 classname :: (scope resolution operator) and the staticfunction();
01:09 Let us see an example on static memebers.
01:13 I have already typed the code on the editor.
01:17 Note that our file name is static dot cpp.
01:21 Let me explain the code now.
01:24 This is our header file as iostream.
01:27 Here we are using the std namespace.
01:31 Then we have class statex.
01:34 In this, we have a non-static variable as 'x' declared as private.
01:40 Then we have a static variable sum declared as public.
01:45 This is our constructor statex.
01:48 In this, we have incremented sum.
01:52 Then the value of sum is stored in 'x'.
01:55 Here we have a static function stat.
01:58 In this, we print the sum.
02:01 Then we have function number().
02:04 Here we print the number 'x'.
02:07 The class is closed here.
02:10 To declare the static variable globally, we use scope resolution operator.
02:15 To access a static variable we write as:
02:19 datatype classname scope resolution operator and the static variable name.
02:26 Now the storage is allocated to variable sum.
02:31 It is initialized to 0.
02:33 This is our main() function.
02:35 Here, we create objects of class statex
02:39 as o1, o2 and o3.
02:42 Then we call the function number() using the objects o1, o2 and o3.
02:49 Static function stat() is accessed here
02:52 using the class name and the scope resolution operator.
02:56 Here, we print the static variable sum.
03:00 And this is our return statement.
03:03 Let us execute the program.
03:05 Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
03:13 To compile, type:
03:15 g++ space static dot cpp space hyphen o space stat. Press Enter.
03:24 Type: ./stat (dot slash stat). Press Enter.
03:28 The output is displayed as:
03:30 Number is: 0, 1, 2
03:33 Result is: 3
03:35 Now static var sum is 3.
03:38 Now, I will explain the output. Let me resize the window.
03:42 Here, first the value of number is 0 i.e.' x' is 0.
03:49 The first object gives the value as 0.
03:53 Then we have the value as 1 i.e. x =1.
03:58 The second object gives the value as 1.
04:01 And the third object gives the value as 2.
04:05 Then we call the stat() function which gives the value of sum.
04:10 Result is: sum.
04:13 Here, sum is incremented and stored in x.
04:18 Hence, this will give the value as 3.
04:22 Thus the final output we have is.
04:25 Static var sum is 3.
04:28 Now, let us create another object here as o4.
04:34 I will call the function number() using the object o4.
04:43 Click on Save.
04:45 Let us execute.
04:48 Press the up arrow key twice.
04:51 Again press the up arrow key twice.
04:54 You can see that Result is 4.
04:57 Now static var sum is 4.
05:00 As the 4th object is created.
05:03 This brings us to the end of this tutorial.
05:06 Come back to our slides.
05:08 Let us summarize.
05:10 In this tutorial, we learned:
05:12 static keyword static variable
05:15 eg. static int sum;
05:18 static function. eg. static void stat()
05:22 As an assignment- Create a class that declares a static variable,
05:26 decrement the variable,
05:29 And print the value.
05:31 Watch the video available at the link shown below.
05:34 It summarizes the Spoken Tutorial project.
05:37 If you do not have good bandwidth, you can download and watch it.
05:41 The Spoken Tutorial Project Team:
05:44 Conducts workshops using spoken tutorials.
05:47 Gives certificates to those who pass an online test.
05:51 For more details, please write to, contact@spoken-tutorial.org
05:58 Spoken Tutorial Project is a part of the "Talk to a Teacher" project.
06:02 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
06:08 More information on this mission is available at the link shown below.
06:13 This is Ashwini Patil from IIT Bombay, signing off.Thank You for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14