C-and-C++/C2/First-C-Program/English-timed
From Script | Spoken-Tutorial
Revision as of 11:12, 17 October 2013 by Sakinashaikh (Talk | contribs)
Time | Narration
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00.02 | Welcome to the spoken tutorial on First C program. |
00.06 | In this tutorial, we will learn |
00.08 | How to write a simple C program |
00.11 | How to compile it |
00.13 | How to execute it |
00.14 | We will also explain some common errors and their solutions. |
00.19 | To record this tutorial, I am using |
00.21 | Ubuntu operating system version 11.10 and gcc Compiler version 4.6.1 on Ubuntu |
00.31 | To practice this tutorial, |
00.33 | You should be familiar with Ubuntu Operating System and an Editor |
00.39 | Some editors are vim and gedit |
00.42 | I will use gedit in this tutorial |
00.46 | For relevant tutorials please visit our website: http://spoken-tutorial.org |
00.51 | Let me tell you how to write a C program through an example |
00.56 | Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard. |
01.07 | Now let's open the text editor. So, at the prompt, type |
01.12 | “gedit” space “talk” dot “c” space “&” |
01.20 | We use ampersand (&) to free up the prompt |
01.25 | Please note that all the C files will have extension dot “c” |
01.31 | Now Press Enter |
01.33 | the text editor has opened |
01.37 | Let us start to write a program |
01.39 | Type double slash “//” space |
01.42 | “My first C program”. |
01.48 | Here, double slash is used to comment the line |
01.52 | Comments are used to understand the flow of program |
01.56 | It is useful for documentation |
01.58 | It gives us information about the program |
02.01 | The double slash is called as single line comment. |
02.07 | Now press Enter |
02.09 | Type hash “#include” space opening bracket , closing bracket |
02.17 | It is always a good practice to complete the brackets first, and then start writing inside it |
02.30 | stdio.h is a header file |
02.33 | A program must contain this header file when it uses standard input/output functions.Now press Enter |
02.43 | type “int” space “main” opening bracket,
closing bracket “()”. |
02.50 | ' main is a special function |
02.52 | It denotes that the execution of the program begins from this line |
02.58 | The opening bracket and closing bracket is called as parenthesis. |
03.04 | Parenthesis followed by main is to tell the user that main is a function |
03.11 | Here the int main function takes no arguments |
03.15 | It returns a value of type integer. |
03.19 | We will learn about data types in another tutorial. |
03.23 | Now Let us switch to the slides to know more about main function. Let us go to the next slide. |
03.30 | Every programshould have one main function |
03.33 | There should NOT be more than one main function |
03.37 | Otherwise the compiler cannot locate the beginning of the program |
03.41 | The empty pair of parentheses indicates that main has no arguments |
03.46 | The concept of arguments will be discussed in detail in the upcoming tutorials. |
03.52 | Now let us come back to our program. Press Enter. |
03.58 | Type opening curly brace “{” |
04.00 | The opening curly bracket marks the beginning of the function main. |
04.05 | Then Type closing curly bracket “}” |
04.08 | The closing curly bracket indicates the end of the function main. |
04.13 | Now Inside the bracket |
04.14 | press Enter twice, move the cursor one line up |
04.20 | Indentation makes the code easier to read |
04.23 | It also helps to locate errors faster |
04.26 | So let us give three space here |
04.29 | And Type “printf” opening bracket closing bracket “()” |
04.34 | printf is a standard C function to print the output on the terminal |
04.39 | Here inside the brackets, within double quotes, |
04.44 | Anything within the double quotes in the printf statement will be printed on the terminal. |
04.50 | Type“Talk To a Teacher backslash n” |
05.00 | Backslash n “\n” signifies newline |
05.03 | As a result, after execution of the printf function, the cursor moves to the new line |
05.11 | Every C statement must end with a semicolon “;” |
05.15 | Hence, type it at the end of this line. |
05.19 | Semicolon acts as a statement terminator. |
05.24 | Now press Enter give three space here |
05.28 | And type “return” space “0” and a semicolon “;” |
05.34 | This statement returns the integer zero |
05.38 | An integer has to be returned for this function because the function type is int |
05.45 | The return statement marks the end of executable statements |
05.51 | We will learn more about the returned values in another tutorial. |
05.56 | Now click on"Save" button to save the file |
06.00 | It is a good habit to save files frequently |
06.03 | This will protect you from sudden power failures |
06.06 | It will also be useful in case the applications were to crash. |
06.10 | Let us now compile the program come back to a terminal. |
06.15 | Type “gcc” space “talk.c” space hyphen “-o” space “myoutput” |
06.24 | gcc is the compiler |
06.27 | talk.c is our filename . |
06.30 | -o myoutput says that the executable should go to the file myoutput |
06.37 | Now Press Enter. |
06.39 | We see that the program is compiled |
06.42 | By typing ls -lrt, we can see that myoutput is the last file to be created |
06.54 | To execute the program, type dot slash “./myoutput” press Enter. |
07.01 | Here the output is displayed as “Talk To a Teacher”. |
07.06 | As I said before, return is the last statement to be executed |
07.10 | Thus after the return statement nothing will be executed. Let us try it out. |
07.15 | come back to our program. |
07.17 | After the return statement, let us include one more printf statement give space here type printf("Welcome \n") at the end type a semicolon. |
07.35 | Now click on save. |
07.37 | Let us compile and execute come back to our terminal. |
07.41 | you can recall the previously entered commands by using up arrowkey. |
07.46 | That is what I did now |
07.51 | We see that the second statements welcome is not executed |
07.58 | Now come back to our program |
08.00 | Let us write the 'Welcome' statement above the return statement |
08.07 | Click on Save. |
08.09 | Let us compile and execute |
08.15 | We see that the second printf statement welcome has also has been executed |
08.23 | Now let us see the common errors which we can come across. Come back to our program.
|
08.29 | Suppose here I will the miss the dot in “stdio.h” Click on save.
|
08.36 | Let us compile and execute . |
08.41 | We see that |
08.42 | There is a fatal error at line no.2 in our talk.c file. |
08.48 | The compiler cannot find a header file with the name “stdioh”hence it is giving an error no such file or directory. |
08.59 | And the compilation is terminated. |
09.03 | Let us now fix the error come back to a program Reinsert the dot “.”click on save
|
09.11 | Let us compile and execute.Yes It is working. |
09.19 | I will show you another common error |
09.22 | Let us switch back to the program.
|
09.26 | Now, suppose here i will miss the semicolon at the end of the line |
09.31 | Click on Save.Let us compile and execute |
09.41 | We see that there is an error at line no.6 in our talk.c file. That expected semicolon before printf. |
09.51 | Come back to our program. As i said before semicolon acts as a statement terminator
|
09.59 | So it will search for it at the end of the line.5 and at the beginning of the line.6. |
10.07 | This is line 6 |
10.09 | This is the last place where you can put the semicolon |
10.13 | Recall that the compiler also give the error message on line 6. |
10.18 | Let us try what happens if we put the semicolon here. |
10.24 | Click on Save . |
10.26 | Let us Compile and execute.Yes it is working |
10.33 | Now come back to our program. Let us type the semicolon here at the end of this line.
|
10.41 | As it is a conventional practice to type the semicolon at the end of the line. Now click on save. |
10.49 | Let us Compile and execute. .Yes it is working.
|
10.49 | Now let us go back to our slides. |
10.57 | As an Assignment |
10.59 | Write a program to print "Welcome to the World of C" |
11.03 | See what happens if “\n” is not included in the printf statement. |
11.09 | This brings us to the end of this tutorial |
11.12 | Watch the video available at the link shown below, http://spokentutorial.org/What\_is\_a\_Spoken\_Tutorial |
11.15 | It summarises the Spoken Tutorial project |
11.18 | If you do not have good bandwidth, you can download and watch it. |
11.22 | The Spoken Tutorial Project Team |
11.24 | Conducts workshops using spoken tutorials |
11.28 | Gives certificates to those who pass an online test |
11.32 | For more details, please write to contact [at] spoken hyphen tutorial dot org |
11.38 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
11.42 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |
11.48 | More information on this Mission is available at the link shown below: http://spoken-tutorial.org\NMEICT-Intro |
11.51 | This is Ashwini Patil from IIT Bombay. Thank you for joining. |
Contributors and Content Editors
Ashwini, Devraj, Krupali, PoojaMoolya, Pratik kamble, Sakinashaikh, Sandhya.np14, Sanmugam, Sneha