C-and-C++/C2/First-C++-Program/English-timed

Time	Narration
00:02	Welcome to the spoken tutorial on First C++ program.
00:07	In this tutorial I am going to explain,
00:10	*How to write a C++ program
00:13	*How to compile it, How to execute it
00:17	We will also explain some common errors and their solution.
00:22	To record this tutorial, I am using Ubuntu operating system version 11.10 and
00:29	G++ Compiler version 4.5.2 on Ubuntu.
00:35	To practice this tutorial,
00:37	You should be familiar with Ubuntu Operating System and an Editor
00:44	Some editors are 'vim' and 'gedit'.
00:48	I am using 'gedit' in this tutorial.
00:50	For relevant tutorial please visit our website which is as shown.
00:56	Let me tell you how to write a C++ program through an example.
01:01	Open the terminal Window using Ctrl, Alt and T keys simultaneously on your keyboard.
01:09	To open the text editor, type on the terminal.
01:13	“gedit” space “talk” dot “.cpp” space ampersand “&” sign.
01:21	We use the “&” to free up the prompt.
01:25	Please note that all the C++ files will have the extension “.cpp”.
01:31	Now Press Enter,
01:33	the text editor has opened.
01:35	Let us start to write a program.
01:38	Type double slash “//” space “My first C++ program”.
01:44	Here, double slash is used to comment the line.
01:49	Comments are used to understand the flow of program.
01:52	It is useful for documentation.
01:55	It gives us information about the program.
01:59	The double slash is called as single line comment. Now press Enter.
02:05	Type (hash) “#include”, space, opening angle bracket, closing angle bracket .
02:13	It is a good practice to complete the brackets first, and then start writing inside it.
02:20	Now Inside the bracket, type “iostream” .
02:23	Here iostream is a header file.
02:26	This file includes the declaration of standard input output functions in C++. Now press Enter.
02:35	Type “using” space “namespace” space “std” and a semicolon “;” .
02:45	The using statement informs the compiler that you want to use the std namespace.
02:52	The purpose of namespace is to avoid name collisions.
02:56	It is done by localizing the names of identifiers.
03:00	It creates a declarative region and defines a scope.
03:05	Anything defined within a namespace is in the SCOPE of that namespace.
03:11	Here std is the namespace in which entire standard C++ library is declared. Now press Enter.
03:20	Type “int” space “main” opening bracket, closing bracket .
03:26	main is a special function.
03:30	It denotes that the execution of the program begins from this line.
03:34	The opening and the closing bracket is called as Parenthesis.
03:39	Parenthesis followed by main tells the user that main is a function.
03:45	Here, the int main() function takes no arguments and returns a value of type integer.
03:52	We will learn about data types in another tutorial.
03:56	Now let us switch to the slides to know more about main function.
04:02	Every program should have one main function.
04:04	There should NOT be more than one “main” function.
04:09	Otherwise the compiler cannot locate the beginning of the program.
04:13	The empty pair of parentheses indicates that main has no arguments.
04:19	The concept of arguments will be discussed in the upcoming tutorials.
04:24	Now come back to our program. Press Enter.
04:29	Type opening curly bracket “{”.
04:32	The opening curly bracket marks the beginning of the function main().
04:37	Then Type closing curly bracket “}”.
04:40	The closing bracket indicates the end of the function main().
04:45	Now, inside the bracket press enter twice.
04:49	Move the cursor one line up.
04:51	Indentation makes the code easier to read.
04:54	It also helps to locate errors faster.
04:58	So let us give a space here.
05:01	And type “cout” space two opening angle bracket '.
05:07	Here cout is a standard C++ function to print the output on the terminal.
05:14	Now after the brackets, type within double quotes.
05:18	Anything within the double quotes, in the cout functions, will be printed.
05:24	Now inside a quote type“Talk to a teacher backslash n” (\n).
05:31	Here \n signifies newline.
05:35	As a result, after execution of the cout function, the cursor moves to the new line.
05:41	Every C++ statement must end with a semicolon.
05:45	Hence type it at the end of this line.
05:48	Semicolon acts as a statement terminator. Now press Enter.
05:53	Give a space here and Type “return” space “0” and a semicolon “;”.
06:00	This statement returns the integer zero.
06:03	An integer has to be returned for this function because the function type is int.
06:10	The return statement marks the end of executable statements.
06:14	We will learn more about the returned values in another tutorial.
06:20	Now click on “Save” button to save the file.
06:23	It is a good habit to save files frequently.
06:26	This will protect you from sudden power failures.
06:30	It will also be useful in case the applications were to crash.
06:34	Let us now compile the program.
06:36	Come back to our terminal.
06:39	Type “g++” space “talk.cpp” space hyphen “-o” space “output”.
06:49	Here g++ is the compiler used to compile C++ programs.
06:55	talk.cpp is our filename.
06:59	hyphen -o output says that the executable should go to the file "output".
07:05	Now press Enter.
07:07	We see that the program is compiled.
07:10	By typing ls space hyphen lrt, we can see that output is the last file to be created.
07:19	Let us execute a program, type “./output” (dot slash output).
07:24	And Press Enter.
07:27	Here the output is displayed as “Talk to a teacher”.
07:30	Now let us see the common errors which we can come across.
07:35	Switch back to our text editor.
07:38	Suppose here we miss the }(closing curly bracket)
07:42	now save the file.
07:44	Let us execute. Come back to our terminal.
07:48	Now compile and run the program using the command we used before. We see an error.
07:55	We see that there is an error at line no.7 in our talk.cpp file that "expected curly bracket at the end of input".
08:07	Now Come back to our text editor .
08:09	As I said before, the closing curly bracket marks the end of the function main
08:14	Hence re-insert the bracket here. Now Save the file.
08:19	Let us execute it again.
08:21	You can recall the previously entered commands by using up arrow key.
08:26	That is what I did now.
08:30	Yes, it is working.
08:32	I will show you another common error.
08:35	Let us switch back to our text editor.
08:37	Now, suppose here we missed std.
08:41	Let us save the file.
08:44	Come back to our terminal .
08:46	Let us compile .
08:48	We see that there is an error at line no.3 and line no.6 in our talk.cpp file.
08:56	That "expected identifier before 'semicolon' " and " 'cout' was not declared in this scope".
09:05	As cout is the standard C++ library function.
09:09	and the entire C++ library function is defined under std namespace .
09:15	Hence it is giving an error.
09:18	Let us now fix the error.Come back to our Text editor. Type std here.
09:23	Let us save it.
09:25	Let us compile it again.
09:29	Yes, it is working.
09:32	As an assignment,
09:33	write a program to print your name and city.
09:37	We used single line comment in this tutorial.
09:40	Now just try to give a multiline comment.
09:44	Watch the video available at the link shown below.
09:46	It summarizes the Spoken Tutorial project.
09:48	If you do not have good bandwidth, you can download and watch it.
09:53	The Spoken Tutorial Project Team:
09:55	Conducts workshops using spoken tutorials.
09:58	Gives certificates to those who pass an online test.
10:01	For more details, please write to contact @spoken-tutorial.org
10:10	Spoken Tutorial Project is a part of the Talk to a Teacher project.
10:14	It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:20	More information on this Mission is available at the link shown below.
10:25	This is Ashwini Patil from IIT Bombay signing off.
10:28	Thank you for watching.

Contributors and Content Editors

Ashwini, Devraj, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha