C-and-C++/C2/First-C++-Program/English-timed
From Script | Spoken-Tutorial
Time' | Narration |
00.01 | Welcome to the spoken tutorial on First C++ program. |
00.06 | In this tutorial I am going to explain, |
00.10 | How to write a C++ program |
00.12 | How to compile it |
00.14 | How to execute it |
00.16 | We will also explain some common errors and their solution. |
00.21 | To record this tutorial, I am using Ubuntu operating system version 11.10 and G++ Compiler version 4.5.2 on Ubuntu. |
00.34 | To practice this tutorial, |
00.36 | You should be familiar with Ubuntu Operating System and an Editor |
00.42 | Some editors are vim and gedit |
00.46 | I am using gedit in this tutorial |
00.49 | For relevant tutorial Please visit our website: http://spoken-tutorial.org |
00.54 | Let me tell you how to write a C++ program through an example |
00.59 | Open the terminal Window using Ctrl, Alt and T keys simultaneously on your keyboard. |
01.08 | To open the text editor, type under terminal. |
01.12 | “gedit” space “talk” dot “.cpp” space ampersand “&”. |
01.20 | We use the “&” to free up the prompt. |
01.24 | Please note that all the C++ files will have the extension “.cpp” |
01.30 | Now Press Enter |
01.32 | the text editor has opened. |
01.35 | Let us start to write a program. |
01.38 | Type double slash “//” space |
01.41 | “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 |
01.53 | It is useful for documentation |
01.55 | It gives us information about the program |
01.58 | The double slash is called as single line comment.Now press Enter. |
02.04 | Type hash “#include” space opening angle bracket closing angle bracket .
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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” . |
02.24 | Here iostream is a header file |
02.28 | This file includes the declaration of standard input output functions in C++.Now press Enter |
02.36 | Type “using” space “namespace” space “std” and a semicolon “;” . |
02.48 | The using statement informs the compiler that you want to use the std namespace |
02.54 | The purpose of namespace is to avoid name collisions |
02.58 | It is done by localizing the names of identifiers |
03.02 | 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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03.28 | main is a special function |
03.31 | It denotes that the execution of the program begins from this line. |
03.36 | The opening and the closing bracket is called as Parenthesis. |
03.41 | Parenthesis followed by main tells the user that main is a function. |
03.48 | Here the int main function takes no arguments and returns a value of type integer. |
03.55 | We will learn about data types in another tutorial. |
04.00 | Now Let us switch to the slides to know more about main function. |
04.06 | Every programshould have one main function |
04.09 | There should NOT be more than one “main” function |
04.13 | Otherwise the compiler cannot locate the beginning of the program |
04.17 | The empty pair of parentheses indicates that main has no arguments |
04.23 | The concept of arguments will be discussed in the upcoming tutorials. Now come back to our program. press enter. |
04.34 | Type opening curly bracket “{” |
04.37 | The opening curly bracket marks the beginning of the function main. |
04.42 | Then Type closing curly bracket “}” |
04.45 | The closing bracket indicates the end of the function main |
04.50 | Now Inside the bracket press enter twice |
04.54 | Move the cursor one line up. |
04.57 | Indentation makes the code easier to read |
05.00 | It also helps to locate errors faster |
05.03 | So let us give a space here. |
05.06 | And type “cout” space two opening angle bracket ' |
05.13 | Here cout is a standard C++ function to print the output on the terminal.
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05.20 | Now after the brackets, type within double quotes |
05.26 | Anything within the double quotes in the cout functions will be printed. Now inside a quote type“Talk to a teacher backslash \n”. |
05.39 | Here \n signifies newline |
05.43 | As a result, after execution of the cout function, the cursor moves to the new line. |
05.50 | Every C++ statement must end with a semicolon
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05.54 | Hence type it at the end of this line. |
05.57 | Semicolon acts as a statement terminator. Now press Enter. |
06.03 | Give a space here and Type “return” space “0” and a semicolon “;”. |
06.10 | This statement returns the integer zero
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06.14 | An integer has to be returned for this function
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06.17 | Because the function type is int
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06.21 | The return statement marks the end of executable statements
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06.26 | We will learn more about the returned values in another tutorial. |
06.31 | Now click on “Save” button to save the file
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06.36 | It is a good habit to save files frequently
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06.39 | This will protect you from sudden power failures
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06.42 | It will also be useful in case the applications were to crash. |
06.47 | Let us now compile the program. |
06.50 | Come back to a terminal
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06.53 | Type “g++” space “talk.cpp” space hyphen “-o” space “output”. |
07.05 | Here g++ is the compiler used to compile C++ programs
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07.12 | talk.cpp is our filename |
07.16 | -o output says that the executable should go to the file output. Now press enter |
07.25 | We see that the program is compiled. |
07.27 | By typing ls -lrt, we can see that output is the last file to be created. |
07.37 | Let us execute a program, type dot slash “./output”
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07.43 | And Press Enter. |
07.46 | Here the output is displayed as “Talk to a teacher”. |
07.50 | Now let us see the common errors which we can come across
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07.54 | switch back to a editor. |
07.57 | Suppose here we miss the {. |
08.01 | Now save the file. |
08.04 | Let us execute.Come back to a terminal |
08.08 | Now compile and run the program using the command we used before. |
08.15 | we see that there is an error at line no.7 in our talk.cpp file
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08.22 | That Expected curly bracket at the end of input. |
08.28 | Now Come back to a text editor . |
08.31 | As i said before the closing curly bracket marks the end of the function main
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08.36 | Hence reinsert the bracket here now Save the file.
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08.41 | Let us execute it
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08.44 | You can recall the previously entered commands by using up arrow key
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08.49 | That is what I did now. Yes it is working. |
08.56 | I will show you another common error
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08.59 | Let us switch back to our text editor. |
09.02 | Now, suppose here we missed std.Let us save the file |
09.08 | Come back to our terminal . Let us compile .
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09.13 | We see that there is an errors at line no 3 and line no 6 in our talk.cpp file
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09.21 | That expected identifier before semicolon and cout was not declared in this scope. |
09.30 | As cout is the standard C++ library function
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09.33 | and the entire C++ library function is defined under std namespace
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09.39 | Hence it is giving an error. |
09.42 | Let us now fix the error
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09.44 | Come back to our Text editor type std at line no-3. |
09.50 | Let us Save it. |
09.52 | Let us compile it again.Yes it is working. Now let us go back to our slide.
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10.02 | As an assignment,
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10.04 | Write a program to print your name and city
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10.07 | We used single line comment in this tutorial
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10.10 | Now just try to give a multiline comment
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10.14 | This brings us to the end of these tutorial . |
10.17 | Watch the video available at the link shown http://spoken-tutorial.org /What\_is\_a\_Spoken\_Tutorial
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10.20 | It summarises the Spoken Tutorial project
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10.22 | If you do not have good bandwidth, you can download and watch it. |
10.26 | The Spoken Tutorial Project Team
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10.28 | Conducts workshops using spoken tutorials
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10.31 | Gives certificates to those who pass an online test
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10.35 | For more details, please write to contact @spoken-tutorial.org |
10.43 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
10.47 | It is supported by the National Mission on Education through ICT, MHRD, Government of India
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10.53 | More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro |
10.58 | This is Ashwini Patil from IIT Bombay signing off
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11.01 | Thank you for watching |
Contributors and Content Editors
Ashwini, Devraj, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha