Difference between revisions of "C-and-C++/C2/First-C++-Program/English-timed"
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| 00:02 | | 00:02 | ||
− | | Welcome to the spoken tutorial on First C++ program. | + | | Welcome to the spoken tutorial on '''First C++ program'''. |
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| 00:10 | | 00:10 | ||
− | | How to write a C++ program | + | | *How to write a C++ program |
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| 00:13 | | 00:13 | ||
− | | How to compile it | + | | *How to compile it |
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| 00:14 | | 00:14 | ||
− | | How to execute it | + | | *How to execute it |
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| 00:44 | | 00:44 | ||
− | |Some editors are vim and gedit | + | |Some editors are 'vim' and 'gedit'. |
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| 00:48 | | 00:48 | ||
− | | I am using gedit in this tutorial | + | | I am using 'gedit' in this tutorial. |
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| 00:50 | | 00:50 | ||
− | | For relevant tutorial | + | | For relevant tutorial please visit our website which is as shown. |
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| 00:56 | | 00:56 | ||
− | | Let me tell you how to write a C++ program through an example | + | | Let me tell you how to write a C++ program through an example. |
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| 01:25 | | 01:25 | ||
− | | Please note that all the C++ files will have the extension '''“.cpp”''' | + | | Please note that all the C++ files will have the extension '''“.cpp”'''. |
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| 01:31 | | 01:31 | ||
− | | Now Press '''Enter''' | + | | Now Press '''Enter''', |
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| 01:44 | | 01:44 | ||
− | | Here, double slash is used to comment the line | + | | Here, double slash is used to comment the line. |
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| 01:49 | | 01:49 | ||
− | | Comments are used to understand the flow of program | + | | Comments are used to understand the flow of program. |
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| 01:52 | | 01:52 | ||
− | | It is useful for documentation | + | | It is useful for documentation. |
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| 01:55 | | 01:55 | ||
− | | It gives us information about the program | + | | It gives us information about the program. |
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| 02:13 | | 02:13 | ||
− | |It is a good practice to complete the brackets first, and then start writing inside it | + | |It is a good practice to complete the brackets first, and then start writing inside it. |
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| 02:23 | | 02:23 | ||
− | | Here '''iostream''' is a '''header file''' | + | | Here '''iostream''' is a '''header file'''. |
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| 02:26 | | 02:26 | ||
− | | This file includes the declaration of standard input output functions in '''C++.''' Now press '''Enter''' | + | | This file includes the declaration of standard input output functions in '''C++.''' Now press '''Enter'''. |
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|02:45 | |02:45 | ||
− | | The '''using''' statement informs the compiler that you want to use the '''std namespace''' | + | | The '''using''' statement informs the compiler that you want to use the '''std namespace'''. |
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| 02:52 | | 02:52 | ||
− | | The purpose of '''namespace''' is to avoid name collisions | + | | The purpose of '''namespace''' is to avoid name collisions. |
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| 02:56 | | 02:56 | ||
− | | It is done by localizing the names of identifiers | + | | It is done by localizing the names of identifiers. |
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|03:00 | |03:00 | ||
− | | It creates a declarative region and defines a scope | + | | It creates a declarative region and defines a scope. |
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| 03:05 | | 03:05 | ||
− | | Anything defined within a '''namespace''' is in the SCOPE of that namespace | + | | Anything defined within a '''namespace''' is in the SCOPE of that namespace. |
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| 03:26 | | 03:26 | ||
− | | '''main''' is a special '''function''' | + | | '''main''' is a special '''function'''. |
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| 03:45 | | 03:45 | ||
− | | Here the '''int''' '''main''' '''function''' takes no '''arguments''' and returns a value of type integer. | + | | Here, the '''int''' '''main''' '''function''' takes no '''arguments''' and returns a value of type integer. |
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| 04:02 | | 04:02 | ||
− | | Every '''program'''should have one main function | + | | Every '''program'''should have one main function. |
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| 04:04 | | 04:04 | ||
− | | There should NOT be more than one “main” function | + | | There should NOT be more than one “main” function. |
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| 04:09 | | 04:09 | ||
− | | Otherwise the compiler cannot locate the beginning of the program | + | | Otherwise the compiler cannot locate the beginning of the program. |
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| 04:13 | | 04:13 | ||
− | | The empty pair of parentheses indicates that main has no '''arguments''' | + | | The empty pair of parentheses indicates that main has no '''arguments'''. |
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| 04:24 | | 04:24 | ||
− | | Now come back to our program. Press | + | | Now come back to our program. Press Enter. |
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| 04:29 | | 04:29 | ||
− | | Type opening curly bracket '''“{”''' | + | | Type opening curly bracket '''“{”'''. |
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| 04:32 | | 04:32 | ||
− | | The opening curly bracket marks the beginning of the '''function main. ''' | + | | The opening curly bracket marks the beginning of the '''function main(). ''' |
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| 04:37 | | 04:37 | ||
− | |Then Type closing curly bracket '''“}”''' | + | |Then Type closing curly bracket '''“}”'''. |
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| 04:40 | | 04:40 | ||
− | | The closing bracket indicates the end of the '''function main ''' | + | | The closing bracket indicates the end of the '''function main()'''. |
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| 04:45 | | 04:45 | ||
− | |Now | + | |Now, inside the bracket press enter twice. |
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|04:51 | |04:51 | ||
− | | Indentation makes the code easier to read | + | | Indentation makes the code easier to read. |
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| 04:54 | | 04:54 | ||
− | | It also helps to locate errors faster | + | | It also helps to locate errors faster. |
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| 05:01 | | 05:01 | ||
− | |And type '''“cout”''' space two opening angle bracket '''' | + | |And type '''“cout”''' space two opening angle bracket ''''. |
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Revision as of 14:49, 30 January 2015
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 |
00:14 | *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 programshould 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 a 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 errors 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
|
09:19 | 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 summarises 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