Difference between revisions of "C-and-C++/C2/First-C-Program/English-timed"

{| border = 1

{| border = 1

|-

|-

|-

|-

|  In this tutorial, we  will learn

|  In this tutorial, we  will learn

|-

|-

| How to write a simple C program  

| How to write a simple C program  

|-

|-

| How to compile it

| How to compile it

|-

|-

| How to execute it

| How to execute it

|-

|-

|We will also explain some common errors and their solutions.  

|We will also explain some common errors and their solutions.  

|-

|-

|-

|-

|Ubuntu operating system version 11.10 and gcc Compiler version 4.6.1 on Ubuntu

|Ubuntu operating system version 11.10 and gcc Compiler version 4.6.1 on Ubuntu

|-

|-

|  To practice this tutorial,  

|  To practice this tutorial,  

|-

|-

|You should be familiar with Ubuntu Operating System and an Editor

|You should be familiar with Ubuntu Operating System and an Editor

|-

|-

|Some editors are '''vim''' and '''gedit'''

|Some editors are '''vim''' and '''gedit'''

|-

|-

|I will use gedit in this tutorial

|I will use gedit in this tutorial

|-

|-

|For relevant tutorials please visit our website which is as shown

|For relevant tutorials please visit our website which is as shown

|-

|-

| 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  

|-

|-

|Open the terminal window  by pressing '''Ctrl, Alt and T '''keys simultaneously on your keyboard.

|Open the terminal window  by pressing '''Ctrl, Alt and T '''keys simultaneously on your keyboard.

|-

|-

|  Now let's open the text editor. So, at the prompt, type  

|  Now let's open the text editor. So, at the prompt, type  

|-

|-

|'''“gedit”''' space '''“talk”''' dot '''“c”''' space “&”''' sign.

|'''“gedit”''' space '''“talk”''' dot '''“c”''' space “&”''' sign.

|-

|-

|'''We use ampersand (&) to free up the prompt '''

|'''We use ampersand (&) to free up the prompt '''

|-

|-

| Please note that all the '''C''' files will  have  extension dot '''“c”'''

| Please note that all the '''C''' files will  have  extension dot '''“c”'''

|-

|-

|  Now Press '''Enter'''

|  Now Press '''Enter'''

|-

|-

|  the text editor has opened

|  the text editor has opened

|-

|-

|  Let us start to write a program  

|  Let us start to write a program  

|-

|-

| Type double slash '''“//”''' space  

| Type double slash '''“//”''' space  

|-

|-

|'''“My first C program”.'''

|'''“My first C program”.'''

|-

|-

| Here, double slash is used to comment the line

| Here, double slash is used to comment the line

|-

|-

|Comments are used to understand the flow of program

|Comments are used to understand the flow of program

|-

|-

|It is useful for documentation

|It is useful for documentation

|-

|-

|It gives us information about the program

|It gives us information about the program

|-

|-

|The double slash is called as single line comment.

|The double slash is called as single line comment.

|-

|-

| Now press '''Enter'''

| Now press '''Enter'''

|-

|-

|Type hash '''“#include”''' space opening bracket , closing bracket'''  

|Type hash '''“#include”''' space opening bracket , closing bracket'''  

|-

|-

| It is always a good practice to complete the brackets first, and then start writing inside it

| It is always a good practice to complete the brackets first, and then start writing inside it

|-

|-

| Now  Inside the bracket, type'''“stdio”''' “(dot).” “'''h” '''

| Now  Inside the bracket, type'''“stdio”''' “(dot).” “'''h” '''

|-

|-

|  '''stdio.h''' is a '''header file'''

|  '''stdio.h''' is a '''header file'''

|-

|-

|A '''program''' must contain this header file when it uses standard '''input/output functions'''

|A '''program''' must contain this header file when it uses standard '''input/output functions'''

|-

|-

|Now press Enter.

|Now press Enter.

|-

|-

|  type '''“int” '''space''' “main” '''opening bracket,

|  type '''“int” '''space''' “main” '''opening bracket,

  closing bracket .

  closing bracket .

|-

|-

| | ' '''main''' is a special '''function'''  

| | ' '''main''' is a special '''function'''  

|-

|-

|It denotes that the execution of the program begins from this line

|It denotes that the execution of the program begins from this line

|-

|-

|The opening bracket and  closing bracket is called as parenthesis.

|The opening bracket and  closing bracket is called as parenthesis.

|-

|-

|  Parenthesis followed by '''main''' is to tell the user that '''main''' is a '''function'''

|  Parenthesis followed by '''main''' is to tell the user that '''main''' is a '''function'''

|-

|-

| Here the '''int''' '''main function''' takes no '''arguments'''  

| Here the '''int''' '''main function''' takes no '''arguments'''  

|-

|-

|It returns a value of type '''integer'''.

|It returns a value of type '''integer'''.

|-

|-

| We will learn about '''data types''' in another tutorial.

| We will learn about '''data types''' in another tutorial.

|-

|-

| Now  Let us switch to the slides to know more about  '''main function'''. Let us go to the next slide.

| Now  Let us switch to the slides to know more about  '''main function'''. Let us go to the next slide.

|-

|-

|  Every '''program'''should have  one main function

|  Every '''program'''should have  one main function

|-

|-

|There should NOT be more than one main function

|There should NOT be more than one main function

|-

|-

|Otherwise the compiler cannot locate the beginning of the program  

|Otherwise the compiler cannot locate the beginning of the program  

|-

|-

|The empty pair of parentheses indicates that main has no '''arguments'''

|The empty pair of parentheses indicates that main has no '''arguments'''

|-

|-

|The concept of arguments will be discussed in detail in the upcoming tutorials.

|The concept of arguments will be discussed in detail in the upcoming tutorials.

|-

|-

| Now let us come back to our program.  

| Now let us come back to our program.  

|-

|-

| Press Enter.

| Press Enter.

|-

|-

| Type opening curly bracket '''“{”'''

| Type opening curly bracket '''“{”'''

|-

|-

|The opening curly bracket marks the beginning of the '''function''' '''main'''.

|The opening curly bracket marks the beginning of the '''function''' '''main'''.

|-

|-

|Then  Type  closing curly  bracket '''“}”'''

|Then  Type  closing curly  bracket '''“}”'''

   

   

|-

|-

|The closing curly bracket indicates the end of the '''function''' '''main'''.  

|The closing curly bracket indicates the end of the '''function''' '''main'''.  

|-

|-

| Now Inside the bracket  press '''Enter''' twice,   

| Now Inside the bracket  press '''Enter''' twice,   

|-

|-

|move the cursor one line up

|move the cursor one line up

|-

|-

| Indentation makes the code easier to read

| Indentation makes the code easier to read

|-

|-

|It also helps to locate errors faster

|It also helps to locate errors faster

|-

|-

|So let us give three space here

|So let us give three space here

|-

|-

| And  Type''' “printf” ''' opening bracket closing bracket '''“()” '''

| And  Type''' “printf” ''' opening bracket closing bracket '''“()” '''

|-

|-

|'''printf '''is a standard C function to print the output on the terminal  

|'''printf '''is a standard C function to print the output on the terminal  

|-

|-

|  Here inside the brackets, within the double quotes,  

|  Here inside the brackets, within the double quotes,  

|-

|-

|Anything within the double quotes in the printf statement will be printed on the terminal.

|Anything within the double quotes in the printf statement will be printed on the terminal.

|-

|-

|Type'''“Talk To a Teacher '''backslash '''n”'''

|Type'''“Talk To a Teacher '''backslash '''n”'''

|-

|-

|Backslash n '''“\n” '''signifies newline

|Backslash n '''“\n” '''signifies newline

|-

|-

|As a result, after execution of the '''printf '''function, the cursor moves to the new line

|As a result, after execution of the '''printf '''function, the cursor moves to the new line

|-

|-

| Every '''C''' statement must end with a '''semicolon “;”'''

| Every '''C''' statement must end with a '''semicolon “;”'''

|-

|-

|Hence, type it at the end of this line.  

|Hence, type it at the end of this line.  

|-

|-

|'''Semicolon''' acts as a statement terminator.

|'''Semicolon''' acts as a statement terminator.

|-

|-

|Now press '''Enter''' give three space here

|Now press '''Enter''' give three space here

|-

|-

| And type '''“return”''' space''' “0”''' and a '''semicolon'''  

| And type '''“return”''' space''' “0”''' and a '''semicolon'''  

|-

|-

| This statement returns the integer zero

| This statement returns the integer zero

|-

|-

|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'''

|-

|-

|The '''return''' statement marks the end of executable statements

|The '''return''' statement marks the end of executable statements

|-

|-

|We will learn more about the returned values in another tutorial.

|We will learn more about the returned values in another tutorial.

|-

|-

| Now click on"'''Save'''" button to save the file  

| Now click on"'''Save'''" button to save the file  

|-

|-

|It is a good habit to save files frequently

|It is a good habit to save files frequently

|-

|-

|This will protect you from sudden power failures

|This will protect you from sudden power failures

|-

|-

|It will also be useful in case the applications were to crash.

|It will also be useful in case the applications were to crash.

|-

|-

|  Let  us now compile the program, come back to a  terminal.

|  Let  us now compile the program, come back to a  terminal.

|-

|-

|Type '''“gcc”''' space '''“talk.c”''' space hyphen “-'''o”''' space '''“myoutput”'''

|Type '''“gcc”''' space '''“talk.c”''' space hyphen “-'''o”''' space '''“myoutput”'''

|-

|-

| '''gcc''' is the compiler

| '''gcc''' is the compiler

|-

|-

|'''talk.c''' is our filename .

|'''talk.c''' is our filename .

|-

|-

|'''-o''' '''myoutput''' says that the executable should go to the file '''myoutput'''

|'''-o''' '''myoutput''' says that the executable should go to the file '''myoutput'''

|-

|-

|  Now Press''' Enter. '''

|  Now Press''' Enter. '''

|-

|-

|We see that the program is compiled

|We see that the program is compiled

|-

|-

|By typing '''ls space (hypen) -lrt''', we can see that '''myoutput''' is the last file to be created

|By typing '''ls space (hypen) -lrt''', we can see that '''myoutput''' is the last file to be created

|-

|-

|To execute the program, type (dot slash)'''“./myoutput” ''' press '''Enter.'''

|To execute the program, type (dot slash)'''“./myoutput” ''' press '''Enter.'''

|-

|-

|  Here the output is displayed as '''“Talk To a Teacher”.'''

|  Here the output is displayed as '''“Talk To a Teacher”.'''

|-

|-

|  As I said before, return is the last statement to be executed

|  As I said before, return is the last statement to be executed

|-

|-

|Thus after the return statement nothing will be executed. Let us try it out.

|Thus after the return statement nothing will be executed. Let us try it out.

|-

|-

| come back to our program.

| come back to our program.

|-

|-

| After the '''return''' statement, let us include one more '''printf''' statement  

| After the '''return''' statement, let us include one more '''printf''' statement  

|-

|-

| give space here type printf opening bracket, closing bracket.  

| give space here type printf opening bracket, closing bracket.  

|-

|-

| Inside the bracket within the double quotes type Welcome backslash n ,  at the end type a semicolon.

| Inside the bracket within the double quotes type Welcome backslash n ,  at the end type a semicolon.

|-

|-

| Now click on  save.

| Now click on  save.

|-

|-

|Let us compile  and execute come back to our terminal.

|Let us compile  and execute come back to our terminal.

|-

|-

|  you can recall the previously entered commands by using '''up arrow'''key.

|  you can recall the previously entered commands by using '''up arrow'''key.

|-

|-

|That is what I did now

|That is what I did now

|-

|-

|We see that the second  statements  '''welcome''' is  not executed

|We see that the second  statements  '''welcome''' is  not executed

|-

|-

| Now come back to our program

| Now come back to our program

|-

|-

|Let us write the 'Welcome' statement above the return statement

|Let us write the 'Welcome' statement above the return statement

|-

|-

|  Click on  Save.

|  Click on  Save.

|-

|-

|Let us compile and execute

|Let us compile and execute

|-

|-

|We see that the second '''printf''' statement ''welcome'' has also has been executed

|We see that the second '''printf''' statement ''welcome'' has also has been executed

|-

|-

| Now let us see the common errors which we can come across.  Come back to our program.

| Now let us see the common errors which we can come across.  Come back to our program.

|-

|-

| Suppose here I  will the miss the dot in '''“stdio.h”''' Click on save.

| Suppose here I  will the miss the dot in '''“stdio.h”''' Click on save.

|-

|-

| Let us  compile and execute .

| Let us  compile and execute .

|-

|-

|We see that

|We see that

|-

|-

|There is a fatal error  at line no.2 in our '''talk.c''' file.

|There is a fatal error  at line no.2 in our '''talk.c''' file.

|-

|-

|The compiler cannot find a '''header file''' with the name '''“stdioh”'''hence it is giving an error no such file or directory.

|The compiler cannot find a '''header file''' with the name '''“stdioh”'''hence it is giving an error no such file or directory.

|-

|-

|And the compilation is terminated.  

|And the compilation is terminated.  

|-

|-

|Let us  now fix the error come back to a  program.Reinsert the dot '''“.”'''click on save  

|Let us  now fix the error come back to a  program.Reinsert the dot '''“.”'''click on save  

|-

|-

| Let us compile and  execute. Yes  It is working.

| Let us compile and  execute. Yes  It is working.

|-

|-

| I will show you another common error

| I will show you another common error

|-

|-

|Let us switch back to the program.

|Let us switch back to the program.

|-

|-

| Now, suppose here i will miss the '''semicolon'''  at the end of the line  

| Now, suppose here i will miss the '''semicolon'''  at the end of the line  

|-

|-

| Click on  '''Save'''.Let us compile and execute

| Click on  '''Save'''.Let us compile and execute

|-

|-

| We see that there is  an error at line no.6 in our talk.c file.  That expected ''semicolon'' before  printf.

| We see that there is  an error at line no.6 in our talk.c file.  That expected ''semicolon'' before  printf.

|-

|-

|Come back to our program.   

|Come back to our program.   

|-

|-

|As  i said before semicolon acts as a statement terminator

|As  i said before semicolon acts as a statement terminator

|-

|-

|So it will search for it at the end of the line.5 and at the beginning of the  line.6.  

|So it will search for it at the end of the line.5 and at the beginning of the  line.6.  

|-

|-

|  This is line 6

|  This is line 6

|-

|-

|  This is the last place where you can put the '''semicolon'''

|  This is the last place where you can put the '''semicolon'''

|-

|-

|Recall that the compiler also give the error message on line 6.

|Recall that the compiler also give the error message on line 6.

|-

|-

| Let us try what happens if we put the semicolon here.

| Let us try what happens if we put the semicolon here.

|-

|-

| Click on '''Save''' .

| Click on '''Save''' .

|-

|-

|Let us  Compile and execute.

|Let us  Compile and execute.

|-

|-

|Yes it is working  

|Yes it is working  

|-

|-

|Now come back to our program.  Let us type the ''semicolon'' here  at the end of this line.

|Now come back to our program.  Let us type the ''semicolon'' here  at the end of this line.

|-

|-

| As it is a conventional practice to type  the ''semicolon'' at the end of the line.

| As it is a conventional practice to type  the ''semicolon'' at the end of the line.

|-

|-

|  Now click on save.  

|  Now click on save.  

|-

|-

|  Let us  Compile and execute. .Yes it is working.

|  Let us  Compile and execute. .Yes it is working.

|-

|-

|Now let us go back to our slides.  

|Now let us go back to our slides.  

|-

|-

| As an Assignment  

| As an Assignment  

|-

|-

|Write a program to print "Welcome to the World of C"

|Write a program to print "Welcome to the World of C"

|-

|-

|See what happens if  '''“\n”''' is not included in the '''printf''' statement.

|See what happens if  '''“\n”''' is not included in the '''printf''' statement.

|-

|-

| This brings us to the end of this tutorial  

| This brings us to the end of this tutorial  

|-

|-

| Watch the video available at the link shown below,  

| Watch the video available at the link shown below,  

|-

|-

|It summarises the Spoken Tutorial project  

|It summarises the Spoken Tutorial project  

|-

|-

|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.

|-

|-

| The Spoken Tutorial Project Team  

| The Spoken Tutorial Project Team  

|-

|-

|Conducts workshops using spoken tutorials  

|Conducts workshops using spoken tutorials  

|-

|-

|Gives certificates to those who pass an online test  

|Gives certificates to those who pass an online test  

|-

|-

|For more details, please write to contact [at] spoken hyphen tutorial dot org

|For more details, please write to contact [at] spoken hyphen tutorial dot org

|-

|-

| 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

|-

|-

|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

|-

|-

|More information on this Mission is available at  the link shown below:  

|More information on this Mission is available at  the link shown below:  

|-

|-

| This is Ashwini Patil from IIT Bombay signing off. Thank you for watching.  

| This is Ashwini Patil from IIT Bombay signing off. Thank you for watching.  

|}

|}