C-and-C-Plus-Plus/C2/First-C-Program/English-timed
From Script | Spoken-Tutorial
| Visual Cue | Narration |
|---|---|
| 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 |
| 00.22 | 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 |
| 02.24 | Now Inside the bracket, type“stdio” dot”.” “h” |
| 02.30 | stdio.h is a header file |
| 02.34 | 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 |
| 02.53 | 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 |
| 03.47 | 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. |
| 06.11 | 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. |
| 07.16 | come back to our program. |
| 07.17 | After the return statement, let us include one more printf statement type printf("Welcome \n"); |
| 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.
|
| 08.35 | Let us compile and execute . |
| 08.42 | We see that |
| 08.43 | 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 it.Yes It is working. |
| 09.19 | I will show you another common error |
| 09.23 | 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 |
| 09.42 | 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 | 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 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 |
| 11.25 | 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: http://spoken-tutorial.org\NMEICT-Intro |
| 11.51 | This is Ashwini Patil from IIT Bombay. Thank you for joining. |
