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

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