Difference between revisions of "C-and-C++/C2/First-C++-Program/English-timed"
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{| border=1 | {| border=1 | ||
− | || | + | || Time |
− | || | + | || Narration |
|- | |- | ||
− | | 00 | + | | 00:02 |
| Welcome to the spoken tutorial on First C++ program. | | Welcome to the spoken tutorial on First C++ program. | ||
|- | |- | ||
− | | 00 | + | | 00:07 |
| In this tutorial I am going to explain, | | In this tutorial I am going to explain, | ||
|- | |- | ||
− | | 00 | + | | 00:10 |
| How to write a C++ program | | How to write a C++ program | ||
|- | |- | ||
− | | 00 | + | | 00:13 |
| How to compile it | | How to compile it | ||
|- | |- | ||
− | | 00 | + | | 00:14 |
| How to execute it | | How to execute it | ||
|- | |- | ||
− | | 00 | + | | 00:17 |
| We will also explain some common errors and their solution. | | We will also explain some common errors and their solution. | ||
|- | |- | ||
− | | 00 | + | | 00:22 |
| To record this tutorial, I am using Ubuntu operating system version 11.10 and | | To record this tutorial, I am using Ubuntu operating system version 11.10 and | ||
|- | |- | ||
− | | 00 | + | | 00:29 |
| G++ Compiler version 4.5.2 on Ubuntu. | | G++ Compiler version 4.5.2 on Ubuntu. | ||
|- | |- | ||
− | | 00 | + | | 00:35 |
| To practice this tutorial, | | To practice this tutorial, | ||
|- | |- | ||
− | | 00 | + | | 00:37 |
| You should be familiar with Ubuntu Operating System and an Editor | | You should be familiar with Ubuntu Operating System and an Editor | ||
|- | |- | ||
− | | 00 | + | | 00:44 |
|Some editors are vim and gedit | |Some editors are vim and gedit | ||
|- | |- | ||
− | | 00 | + | | 00:48 |
| I am using gedit in this tutorial | | I am using gedit in this tutorial | ||
|- | |- | ||
− | | 00 | + | | 00:50 |
| For relevant tutorial Please visit our website which is as shown | | For relevant tutorial Please visit our website which is as shown | ||
|- | |- | ||
− | | 00 | + | | 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 | ||
|- | |- | ||
− | | 01 | + | | 01:01 |
| Open the terminal Window using '''Ctrl, Alt and T keys''' simultaneously on your keyboard. | | Open the terminal Window using '''Ctrl, Alt and T keys''' simultaneously on your keyboard. | ||
|- | |- | ||
− | | 01 | + | | 01:09 |
| To open the text editor, type on the terminal. | | To open the text editor, type on the terminal. | ||
|- | |- | ||
− | | 01 | + | | 01:13 |
| '''“gedit”''' space '''“talk”''' dot '''“.cpp”''' space ampersand '''“&”''' sign. | | '''“gedit”''' space '''“talk”''' dot '''“.cpp”''' space ampersand '''“&”''' sign. | ||
|- | |- | ||
− | | 01 | + | | 01:21 |
| We use the '''“&”''' to free up the prompt. | | We use the '''“&”''' to free up the prompt. | ||
|- | |- | ||
− | | 01 | + | | 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”''' | ||
|- | |- | ||
− | | 01 | + | | 01:31 |
| Now Press '''Enter''' | | Now Press '''Enter''' | ||
|- | |- | ||
− | | 01 | + | | 01:33 |
|the text editor has opened. | |the text editor has opened. | ||
|- | |- | ||
− | | 01 | + | | 01:35 |
| Let us start to write a program. | | Let us start to write a program. | ||
|- | |- | ||
− | | 01 | + | | 01:38 |
| Type double slash '''“//”''' space '''“My first C++ program”.''' | | Type double slash '''“//”''' space '''“My first C++ program”.''' | ||
|- | |- | ||
− | | 01 | + | | 01:44 |
| Here, double slash is used to comment the line | | Here, double slash is used to comment the line | ||
|- | |- | ||
− | | 01 | + | | 01:49 |
| Comments are used to understand the flow of program | | Comments are used to understand the flow of program | ||
|- | |- | ||
− | | 01 | + | | 01:52 |
| It is useful for documentation | | It is useful for documentation | ||
|- | |- | ||
− | | 01 | + | | 01:55 |
| It gives us information about the program | | It gives us information about the program | ||
|- | |- | ||
− | | 01 | + | | 01:59 |
| The double slash is called as single line comment. Now press Enter. | | The double slash is called as single line comment. Now press Enter. | ||
|- | |- | ||
− | | 02 | + | | 02:05 |
| Type hash '''“#include”''' space opening angle bracket ''' ''closing angle bracket ''' . | | Type hash '''“#include”''' space opening angle bracket ''' ''closing angle bracket ''' . | ||
|- | |- | ||
− | | 02 | + | | 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 | ||
|- | |- | ||
− | | 02 | + | | 02:20 |
| Now Inside the bracket, type '''“iostream”''' . | | Now Inside the bracket, type '''“iostream”''' . | ||
|- | |- | ||
− | | 02 | + | | 02:23 |
| Here '''iostream''' is a '''header file''' | | Here '''iostream''' is a '''header file''' | ||
|- | |- | ||
− | | 02 | + | | 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 | ||
|- | |- | ||
− | | 02 | + | | 02:35 |
| Type '''“using”''' space '''“namespace”''' space '''“std”''' and a semicolon '''“;”''' . | | Type '''“using”''' space '''“namespace”''' space '''“std”''' and a semicolon '''“;”''' . | ||
|- | |- | ||
− | |02 | + | |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''' | ||
|- | |- | ||
− | | 02 | + | | 02:52 |
| The purpose of '''namespace''' is to avoid name collisions | | The purpose of '''namespace''' is to avoid name collisions | ||
|- | |- | ||
− | | 02 | + | | 02:56 |
| It is done by localizing the names of identifiers | | It is done by localizing the names of identifiers | ||
|- | |- | ||
− | |03 | + | |03:00 |
| It creates a declarative region and defines a scope | | It creates a declarative region and defines a scope | ||
|- | |- | ||
− | | 03 | + | | 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 | ||
|- | |- | ||
− | | 03 | + | | 03:11 |
|Here '''std''' is the '''namespace''' in which entire standard C++ library is declared. Now press '''Enter'''. | |Here '''std''' is the '''namespace''' in which entire standard C++ library is declared. Now press '''Enter'''. | ||
|- | |- | ||
− | | 03 | + | | 03:20 |
| Type '''“int”''' space '''“main”''' opening bracket, closing bracket . | | Type '''“int”''' space '''“main”''' opening bracket, closing bracket . | ||
|- | |- | ||
− | | 03 | + | | 03:26 |
| '''main''' is a special '''function''' | | '''main''' is a special '''function''' | ||
|- | |- | ||
− | | 03 | + | | 03:30 |
| It denotes that the execution of the program begins from this line. | | It denotes that the execution of the program begins from this line. | ||
|- | |- | ||
− | | 03 | + | | 03:34 |
|The opening and the closing bracket is called as'' Parenthesis''. | |The opening and the closing bracket is called as'' Parenthesis''. | ||
|- | |- | ||
− | | 03 | + | | 03:39 |
| Parenthesis followed by '''main''' tells the user that '''main''' is a '''function.''' | | Parenthesis followed by '''main''' tells the user that '''main''' is a '''function.''' | ||
|- | |- | ||
− | | 03 | + | | 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. | ||
|- | |- | ||
− | | 03 | + | | 03:52 |
| We will learn about data types in another tutorial. | | We will learn about data types in another tutorial. | ||
|- | |- | ||
− | | 03 | + | | 03:56 |
|Now let us switch to the slides to know more about main function. | |Now let us switch to the slides to know more about main function. | ||
|- | |- | ||
− | | 04 | + | | 04:02 |
| Every '''program'''should have one main function | | Every '''program'''should have one main function | ||
|- | |- | ||
− | | 04 | + | | 04:04 |
| There should NOT be more than one “main” function | | There should NOT be more than one “main” function | ||
|- | |- | ||
− | | 04 | + | | 04:09 |
| Otherwise the compiler cannot locate the beginning of the program | | Otherwise the compiler cannot locate the beginning of the program | ||
|- | |- | ||
− | | 04 | + | | 04:13 |
| The empty pair of parentheses indicates that main has no '''arguments''' | | The empty pair of parentheses indicates that main has no '''arguments''' | ||
|- | |- | ||
− | | 04 | + | | 04:19 |
| The concept of '''arguments''' will be discussed in the upcoming tutorials. | | The concept of '''arguments''' will be discussed in the upcoming tutorials. | ||
|- | |- | ||
− | | 04 | + | | 04:24 |
| Now come back to our program. Press enter. | | Now come back to our program. Press enter. | ||
|- | |- | ||
− | | 04 | + | | 04:29 |
| Type opening curly bracket '''“{”''' | | Type opening curly bracket '''“{”''' | ||
|- | |- | ||
− | | 04 | + | | 04:32 |
| The opening curly bracket marks the beginning of the '''function main. ''' | | The opening curly bracket marks the beginning of the '''function main. ''' | ||
|- | |- | ||
− | | 04 | + | | 04:37 |
|Then Type closing curly bracket '''“}”''' | |Then Type closing curly bracket '''“}”''' | ||
|- | |- | ||
− | | 04 | + | | 04:40 |
| The closing bracket indicates the end of the '''function main ''' | | The closing bracket indicates the end of the '''function main ''' | ||
|- | |- | ||
− | | 04 | + | | 04:45 |
|Now Inside the bracket press enter twice | |Now Inside the bracket press enter twice | ||
|- | |- | ||
− | | 04 | + | | 04:49 |
| Move the cursor one line up. | | Move the cursor one line up. | ||
|- | |- | ||
− | |04 | + | |04:51 |
| Indentation makes the code easier to read | | Indentation makes the code easier to read | ||
|- | |- | ||
− | | 04 | + | | 04:54 |
| It also helps to locate errors faster | | It also helps to locate errors faster | ||
|- | |- | ||
− | | 04 | + | | 04:58 |
|So let us give a space here. | |So let us give a space here. | ||
|- | |- | ||
− | | 05 | + | | 05:01 |
|And type '''“cout”''' space two opening angle bracket '''' | |And type '''“cout”''' space two opening angle bracket '''' | ||
|- | |- | ||
− | | 05 | + | | 05:07 |
| Here '''cout '''is a standard '''C++ function''' to print the output on the terminal. | | Here '''cout '''is a standard '''C++ function''' to print the output on the terminal. | ||
Line 268: | Line 268: | ||
|- | |- | ||
− | | 05 | + | | 05:14 |
|Now after the brackets, type within double quotes ''' | |Now after the brackets, type within double quotes ''' | ||
|- | |- | ||
− | | 05 | + | | 05:18 |
|Anything within the double quotes in the '''cout ''' functions will be printed. | |Anything within the double quotes in the '''cout ''' functions will be printed. | ||
|- | |- | ||
− | | 05 | + | | 05:24 |
|Now inside a quote type“Talk to a teacher backslash n” (/n)'''. | |Now inside a quote type“Talk to a teacher backslash n” (/n)'''. | ||
|- | |- | ||
− | | 05 | + | | 05:31 |
| Here '''\n''' signifies newline | | Here '''\n''' signifies newline | ||
|- | |- | ||
− | | 05 | + | | 05:35 |
| As a result, after execution of the '''cout function''', the cursor moves to the new line. | | As a result, after execution of the '''cout function''', the cursor moves to the new line. | ||
|- | |- | ||
− | | 05 | + | | 05:41 |
| Every C++ statement must end with a '''semicolon''' | | Every C++ statement must end with a '''semicolon''' | ||
|- | |- | ||
− | | 05 | + | | 05:45 |
| Hence type it at the end of this line. | | Hence type it at the end of this line. | ||
|- | |- | ||
− | | 05 | + | | 05:48 |
| Semicolon acts as a statement terminator. Now press Enter. | | Semicolon acts as a statement terminator. Now press Enter. | ||
|- | |- | ||
− | | 05 | + | | 05:53 |
| Give a space here and Type '''“return”''' space '''“0”''' and a semicolon '''“;”.''' | | Give a space here and Type '''“return”''' space '''“0”''' and a semicolon '''“;”.''' | ||
|- | |- | ||
− | | 06 | + | | 06:00 |
| This statement returns the integer zero | | This statement returns the integer zero | ||
|- | |- | ||
− | | 06 | + | | 06:03 |
| An integer has to be returned for this '''function''' because the '''function''' type is '''int''' | | An integer has to be returned for this '''function''' because the '''function''' type is '''int''' | ||
|- | |- | ||
− | | 06 | + | | 06:10 |
| The '''return''' statement marks the end of executable statements | | The '''return''' statement marks the end of executable statements | ||
|- | |- | ||
− | | 06 | + | | 06:14 |
| We will learn more about the returned values in another tutorial. | | We will learn more about the returned values in another tutorial. | ||
|- | |- | ||
− | | 06 | + | | 06:20 |
| Now click on '''“Save”''' button to save the file | | Now click on '''“Save”''' button to save the file | ||
|- | |- | ||
− | | 06 | + | | 06:23 |
| It is a good habit to save files frequently | | It is a good habit to save files frequently | ||
|- | |- | ||
− | | 06 | + | | 06:26 |
| This will protect you from sudden power failures | | This will protect you from sudden power failures | ||
|- | |- | ||
− | | 06 | + | | 06:30 |
| It will also be useful in case the applications were to crash. | | It will also be useful in case the applications were to crash. | ||
|- | |- | ||
− | | 06 | + | | 06:34 |
| Let us now compile the program. | | Let us now compile the program. | ||
|- | |- | ||
− | | 06 | + | | 06:36 |
| Come back to our terminal | | Come back to our terminal | ||
|- | |- | ||
− | | 06 | + | | 06:39 |
| Type '''“g++”''' space '''“talk.cpp”''' space hyphen '''“-o”''' space '''“output”.''' | | Type '''“g++”''' space '''“talk.cpp”''' space hyphen '''“-o”''' space '''“output”.''' | ||
|- | |- | ||
− | | 06 | + | | 06:49 |
|Here '''g++''' is the compiler used to compile '''C++ '''programs | |Here '''g++''' is the compiler used to compile '''C++ '''programs | ||
|- | |- | ||
− | | 06 | + | | 06:55 |
| '''talk.cpp''' is our filename | | '''talk.cpp''' is our filename | ||
|- | |- | ||
− | | 06 | + | | 06:59 |
| '''hyphen -o output''' says that the executable should go to the file output. | | '''hyphen -o output''' says that the executable should go to the file output. | ||
|- | |- | ||
− | | 07 | + | | 07:05 |
| 'Now press enter | | 'Now press enter | ||
|- | |- | ||
− | | 07 | + | | 07:07 |
| We see that the program is compiled. | | We see that the program is compiled. | ||
|- | |- | ||
− | | 07 | + | | 07:10 |
| By typing '''ls space hyphen lrt''', we can see that '''output''' is the last file to be created. | | By typing '''ls space hyphen lrt''', we can see that '''output''' is the last file to be created. | ||
|- | |- | ||
− | | 07 | + | | 07:19 |
| Let us execute a program, type '''“./output” '''(dot slash output). | | Let us execute a program, type '''“./output” '''(dot slash output). | ||
|- | |- | ||
− | | 07 | + | | 07:24 |
|And Press '''Enter.''' | |And Press '''Enter.''' | ||
|- | |- | ||
− | | 07 | + | | 07:27 |
| Here the output is displayed as '''“Talk to a teacher”.''' | | Here the output is displayed as '''“Talk to a teacher”.''' | ||
|- | |- | ||
− | | 07 | + | | 07:30 |
| Now let us see the common errors which we can come across | | Now let us see the common errors which we can come across | ||
|- | |- | ||
− | | 07 | + | | 07:35 |
| switch back to our text editor. | | switch back to our text editor. | ||
|- | |- | ||
− | | 07 | + | | 07:38 |
| Suppose here we miss the '''}'''(closing curly bracket) | | Suppose here we miss the '''}'''(closing curly bracket) | ||
|- | |- | ||
− | | 07 | + | | 07:42 |
|Now save the file. | |Now save the file. | ||
|- | |- | ||
− | | 07 | + | | 07:44 |
| Let us execute. Come back to a terminal | | Let us execute. Come back to a terminal | ||
|- | |- | ||
− | | 07 | + | | 07:48 |
| Now compile and run the program using the command we used before. We see an error | | Now compile and run the program using the command we used before. We see an error | ||
|- | |- | ||
− | | 07 | + | | 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. | | 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 | + | | 08:07 |
|Now Come back to our text editor . | |Now Come back to our text editor . | ||
|- | |- | ||
− | | 08 | + | | 08:09 |
| As i said before the closing curly bracket marks the end of the function main | | As i said before the closing curly bracket marks the end of the function main | ||
|- | |- | ||
− | | 08 | + | | 08:14 |
| Hence re-insert the bracket here. Now Save the file. | | Hence re-insert the bracket here. Now Save the file. | ||
|- | |- | ||
− | | 08 | + | | 08:19 |
| Let us execute it again | | Let us execute it again | ||
|- | |- | ||
− | | 08 | + | | 08:21 |
| You can recall the previously entered commands by using up arrow key | | You can recall the previously entered commands by using up arrow key | ||
|- | |- | ||
− | | 08 | + | | 08:26 |
| That is what I did now. | | That is what I did now. | ||
|- | |- | ||
− | | 08 | + | | 08:30 |
| Yes it is working. | | Yes it is working. | ||
|- | |- | ||
− | |08 | + | |08:32 |
| I will show you another common error | | I will show you another common error | ||
|- | |- | ||
− | | 08 | + | | 08:35 |
| Let us switch back to our text editor. | | Let us switch back to our text editor. | ||
|- | |- | ||
− | | 08 | + | | 08:37 |
| Now, suppose here we missed '''std.''' | | Now, suppose here we missed '''std.''' | ||
|- | |- | ||
− | | 08 | + | | 08:41 |
| Let us save the file | | Let us save the file | ||
|- | |- | ||
− | | 08 | + | | 08:44 |
| Come back to our terminal . | | Come back to our terminal . | ||
|- | |- | ||
− | | 08 | + | | 08:46 |
| Let us compile . | | Let us compile . | ||
|- | |- | ||
− | | 08 | + | | 08:48 |
| We see that there is an errors at line no 3 and line no 6 in our '''talk.cpp''' file | | We see that there is an errors at line no 3 and line no 6 in our '''talk.cpp''' file | ||
|- | |- | ||
− | | 08 | + | | 08:56 |
| That expected identifier before '''semicolon''' and '''cout''' was not declared in this scope. | | That expected identifier before '''semicolon''' and '''cout''' was not declared in this scope. | ||
|- | |- | ||
− | |09 | + | |09:05 |
| As '''cout''' is the standard '''C++ library function''' | | As '''cout''' is the standard '''C++ library function''' | ||
|- | |- | ||
− | | 09 | + | | 09:09 |
| and the entire '''C++ library function''' is defined under '''std namespace ''' | | and the entire '''C++ library function''' is defined under '''std namespace ''' | ||
|- | |- | ||
− | | 09 | + | | 09:15 |
| Hence it is giving an error. | | Hence it is giving an error. | ||
|- | |- | ||
− | | 09 | + | | 09:18 |
| Let us now fix the error | | Let us now fix the error | ||
|- | |- | ||
− | | 09 | + | | 09:19 |
| Come back to our Text editor. Type '''std''' here | | Come back to our Text editor. Type '''std''' here | ||
|- | |- | ||
− | | 09 | + | | 09:23 |
| Let us Save it. | | Let us Save it. | ||
|- | |- | ||
− | | 09 | + | | 09:25 |
| Let us compile it again. | | Let us compile it again. | ||
|- | |- | ||
− | | 09 | + | | 09:29 |
| Yes it is working. | | Yes it is working. | ||
|- | |- | ||
− | | 09 | + | | 09:32 |
| As an assignment, | | As an assignment, | ||
|- | |- | ||
− | | 09 | + | | 09:33 |
| Write a program to print your name and city | | Write a program to print your name and city | ||
|- | |- | ||
− | | 09 | + | | 09:37 |
| We used '''single line comment''' in this tutorial | | We used '''single line comment''' in this tutorial | ||
|- | |- | ||
− | |09 | + | |09:40 |
| Now just try to give a '''multiline comment''' | | Now just try to give a '''multiline comment''' | ||
Line 548: | Line 548: | ||
|- | |- | ||
− | | 09 | + | | 09:44 |
| Watch the video available at the link shown below | | Watch the video available at the link shown below | ||
|- | |- | ||
− | | 09 | + | | 09:46 |
| It summarises the Spoken Tutorial project | | It summarises the Spoken Tutorial project | ||
|- | |- | ||
− | | 09 | + | | 09:48 |
| If you do not have good bandwidth, you can download and watch it. | | If you do not have good bandwidth, you can download and watch it. | ||
|- | |- | ||
− | |09 | + | |09:53 |
|The Spoken Tutorial Project Team | |The Spoken Tutorial Project Team | ||
|- | |- | ||
− | | 09 | + | | 09:55 |
| Conducts workshops using spoken tutorials | | Conducts workshops using spoken tutorials | ||
|- | |- | ||
− | |09 | + | |09:58 |
| Gives certificates to those who pass an online test | | Gives certificates to those who pass an online test | ||
|- | |- | ||
− | | 10 | + | | 10:01 |
| For more details, please write to contact @spoken-tutorial.org | | For more details, please write to contact @spoken-tutorial.org | ||
|- | |- | ||
− | |10 | + | |10:10 |
| Spoken Tutorial Project is a part of the Talk to a Teacher project | | Spoken Tutorial Project is a part of the Talk to a Teacher project | ||
|- | |- | ||
− | | 10 | + | | 10:14 |
| It is supported by the National Mission on Education through ICT, MHRD, Government of India | | It is supported by the National Mission on Education through ICT, MHRD, Government of India | ||
|- | |- | ||
− | | 10 | + | | 10:20 |
| More information on this Mission is available at the link shown below | | More information on this Mission is available at the link shown below | ||
|- | |- | ||
− | | 10 | + | | 10:25 |
| This is Ashwini Patil from IIT Bombay signing off | | This is Ashwini Patil from IIT Bombay signing off | ||
|- | |- | ||
− | | 10 | + | | 10:28 |
| Thank you for watching | | Thank you for watching | ||
|} | |} |
Revision as of 11:22, 23 June 2014
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.
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03:20 | Type “int” space “main” opening bracket, closing bracket .
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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.
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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
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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
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06:03 | An integer has to be returned for this function because the function type is int
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06:10 | The return statement marks the end of executable statements
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06:14 | We will learn more about the returned values in another tutorial. |
06:20 | Now click on “Save” button to save the file
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06:23 | It is a good habit to save files frequently
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06:26 | This will protect you from sudden power failures
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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
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06:39 | Type “g++” space “talk.cpp” space hyphen “-o” space “output”. |
06:49 | Here g++ is the compiler used to compile C++ programs
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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).
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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
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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.
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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
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08:14 | Hence re-insert the bracket here. Now Save the file.
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08:19 | Let us execute it again
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08:21 | You can recall the previously entered commands by using up arrow key
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08:26 | That is what I did now. |
08:30 | Yes it is working.
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08:32 | I will show you another common error
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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
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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
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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
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09:09 | and the entire C++ library function is defined under std namespace
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09:15 | Hence it is giving an error. |
09:18 | Let us now fix the error
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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.
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09:32 | As an assignment,
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09:33 | Write a program to print your name and city
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09:37 | We used single line comment in this tutorial
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09:40 | Now just try to give a multiline comment
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09:44 | Watch the video available at the link shown below |
09:46 | It summarises the Spoken Tutorial project
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09:48 | If you do not have good bandwidth, you can download and watch it. |
09:53 | The Spoken Tutorial Project Team
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09:55 | Conducts workshops using spoken tutorials
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09:58 | Gives certificates to those who pass an online test
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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
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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
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10:28 | Thank you for watching |
Contributors and Content Editors
Ashwini, Devraj, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha