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Time 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
00.21 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
02.24 Now Inside the bracket, type“stdio” dot”.” “h”
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.