C-and-C++/C3/Strings/English-timed

Time	Narration
00:01	Welcome to the spoken-tutorial on Strings in C and C++.
00:06	In this tutorial we will learn:
00:08	* What is a string.
00:10	* Declaration of a string.
00:13	* Initialization of a string.
00:15	* Few examples on string.
00:17	We will also see some common errors and their solutions.
00:22	To record this tutorial, I am using
00:25	Ubuntu Operating System version 11.04,
00:29	gcc and g++ Compiler version 4.6.1 .
00:35	Let us start with the introduction to strings.
00:38	String is a sequence of characters that is treated as a single data item.
00:44	Size of string = length of string + 1.
00:49	Let me tell you how to declare a string.
00:52	The syntax for this is
00:55	char, name of string and size.
00:59	char is the data type, name of the string is the string name, and we can give the size here.
01:06	Eg: here we have declared a character string names with size 10.
01:13	Now we will see an example.
01:15	I have already typed the program, I will open it.
01:19	Note that our file name is string.c
01:23	In this program, we will take a string as an input from the user and print it.
01:29	Let me explain the code now.
01:32	These are our header files.
01:34	Here string.h includes the declarations, functions, constants of string handling utilities.
01:43	Whenever we work on string functions, we should include this header file.
01:47	This is our main() function.
01:49	Here we are declaring the string strname with size 30.
01:55	Here we are accepting a string from the user.
01:58	To read a string, we can use scanf() function with format specifier %s.
02:05	We are using the caret sign and \n to include the spaces with the string.
02:11	Then we print the string.
02:13	And this is our return statement.
02:16	Now click on Save.
02:18	Let us execute the program.
02:20	Please open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
02:30	To compile, type gcc space string.c space -o space str
02:37	And press Enter .
02:40	To execute, type ./str (dot slash str).
02:43	Now press Enter.
02:46	Here it is displayed as Enter the string .
02:49	I will type "Talk To A Teacher".
02:56	Now press Enter.
02:58	The output is displayed as The string is Talk To A Teacher.
03:03	Now let us switch back to our slides.
03:06	Until now we discussed about the declaration of a string.
03:10	Now we are going to discuss how to initialize the string.
03:13	The syntax for this is,
03:16	char var_name[size] = “string”;
03:20	Eg: Here we have declared a character string “names” with size 10 and the string is “Priya”"
03:28	Another syntax is,
03:31	char var_name[ ] = {'S', 't', 'r', 'i', 'n', 'g'} within single quotes.
03:36	eg: char names[10] = {'P', 'r', 'i', 'y', 'a'} in single quotes.
03:42	Let me show you how to use the first syntax with an example.
03:48	Switch back to our Editor. We will use the same example.
03:52	First, press shift, ctrl and s keys simultaneously on your keyboard.
03:58	Now save the file with the name stringinitialize.
04:03	Now click on Save.
04:06	We are going to initialize the string.
04:08	Hence, at the 5th line, type
04:11	= and within the double quotes “Spoken-Tutorial”;
04:20	Now, click on Save .
04:22	Now remove these two lines, as we are only going to print the string.
04:27	Click on Save.
04:30	Let us execute.
04:31	Come back to our terminal.
04:33	To compile, type
04:35	gcc space stringinitialize.c space -o space str2
04:44	Here we have str2 because we don't want to overwrite the output parameter str for the file string.c.
04:54	Now press Enter.
04:56	To execute, type ./str2
05:00	The output is displayed as "The string is Spoken-Tutorial".
05:06	Now we will see some common errors which we can come across .
05:09	Come back to our program.
05:11	Suppose, here we type the spelling of string as sting.
05:16	Now click on Save.
05:18	Let us execute.
05:19	Come back to our terminal.
05:21	Now compile as before.
05:23	We see an fatal error.
05:25	sting.h: No such file or directory
05:28	compilation terminated.
05:30	Come back to our program.
05:32	This is because the compiler is not able to find the header file with the name sting.h .
05:39	Hence it is giving an error.
05:41	Let us fix the error.
05:43	Type r here.
05:45	Now click on Save.
05:46	Let us execute again.
05:47	Come back to our terminal.
05:50	Compile as before, execute as before.
05:54	Yes, it is working!
05:56	Now, let us see another common error.
05:59	Come back to our program.
06:02	Suppose, here I will type int in place of char.
06:06	Now, click on Save .
06:07	Let us see what happens.
06:09	Come back to our terminal.
06:11	Let me clear the prompt.
06:15	Compile as before.
06:17	We see an error.
06:19	Wide character array initialized from non-wide string .
06:24	format %s expects argument of type 'char' but argument 2 has type 'int' .
06:32	Come back to our program.
06:36	This is because we used  %s as the format specifier for string.
06:42	And we are initializing it with an integer data type.
06:47	Let us fix the error.
06:49	Type char here.
06:51	Click on Save.
06:53	Let us execute. Come back to our terminal.
06:56	Compile as before, execute as before.
07:00	Yes, it is working!
07:03	Now we will see how to execute the same program in C++.
07:08	Come back to our program.
07:11	Let me open our file string.c.
07:15	We will edit the code here.
07:18	First, press shift, ctrl and S keys simultaneously on your keyboard.
07:25	Now save the file with an extension .cpp (dot cpp).
07:29	and click on Save.
07:33	Now we will change the header file as iostream.
07:38	Include the using statement.
07:43	Now click on Save.
07:47	Now we will delete this declaration.
07:50	And will declare a string variable.
07:53	Type string space strname and a semicolon.
07:59	Click on Save.
08:02	Replace the printf statement with the cout statement.
08:07	Delete the closing bracket here.
08:11	Delete the scanf statement and type getline opening bracket closing bracket, within the brackets type (cin, strname) .
08:24	At the end, type a semicolon.
08:28	Now again, replace the printf statement with the cout statement.
08:36	Delete the format specifier and \n .
08:40	Now delete the comma.
08:42	Type two opening angle brackets, delete the bracket here.
08:49	Type two opening angle brackets and within the double quotes type \n .
08:54	And click on Save.
08:58	Here we have declared a string variable 'strname' .
09:03	Since we do not use the format specifier in C++, the compiler should know that 'strname' is a string variable.
09:13	Here we use getline to extract the characters from the input sequence.
09:18	It stores them as a string.
09:22	Now let us execute the program. Come back to our terminal.
09:27	Let me clear the prompt.
09:30	To compile, type
09:32	g++ space string.cpp space -o space str3
09:39	and press Enter.
09:41	To execute, type ./str3 (dot slash str3).
09:46	Press Enter.
09:47	It is displayed as Enter the string.
09:50	I will enter as Talk To A Teacher .
09:55	Now press Enter.
09:57	The output is displayed as
09:59	"The string is Talk To A Teacher"
10:03	We can see that the output is similar to our C code.
10:07	Now come back to our slides.
10:10	Let us summarize.
10:11	In this tutorial we learnt:
10:13	*Strings
10:14	*Declaration of a string
10:16	eg: char strname[30]
10:20	*Initialization of a string
10:21	eg: char strname[30] = “Talk To A Teacher”
10:26	As an assignment,
10:28	write a program to print a string using the 2nd syntax.
10:34	Watch the video available at the link shown below.
10:37	It summarizes the Spoken Tutorial project.
10:40	If you do not have good bandwidth, you can download and watch it.
10:44	The Spoken Tutorial Project Team:
10:46	Conducts workshops using spoken tutorials.
10:49	Gives certificates to those who pass an online test.
10:54	For more details, please write to, contact@spoken-tutorial.org.
11:01	Spoken Tutorial Project is a part of Talk to a Teacher project.
11:04	It is supported by the National Mission on Education through ICT, MHRD, Government of India.
11:12	More information on this mission is available at the link shown below.
11:16	This is Ashwini Patil from IIT Bombay, signing off.
11:20	Thank You for watching.

Contributors and Content Editors

Kavita salve, PoojaMoolya, Pratik kamble, Sandhya.np14