Difference between revisions of "BASH/C3/Arrays-and-functions/English-timed"

| Dear friends, Welcome to the spoken tutorial on '''Arrays & functions'''

| In this tutorial, we will learn

| To pass an '''array''' to a''' function '''

| Use of '''return''' statement in a '''function'''

| With the help of some examples  

| To follow this tutorial you should have knowledge of '''Shell Scripting.'''

|You should also have knowledge of '''arrays '''and '''if statement '''in BASH.

|If not, for relevant tutorials please visit our website which is as shown,'''http://www.spoken-tutorial.org'''

| For this tutorial I am using''' '''

| '''Ubuntu Linux''' 12.04''' '''Operating System and

| '''GNU BASH''' version 4.2

| Let us first learn how to pass an '''array''' to a '''function,''' and its usage.

| Let me open a file '''function_(underscore)array dot sh'''

| Our '''function''' name is '''array_(underscore) display'''

|Open curly brace opens the '''function definition.'''

|Basically, it is used to print all '''arguments''' passed to a '''function.'''

|'''Dollar @ (at sign) within round brackets '''stores '''array elements '''in variable ''''array'.'''

| '''Dollar''' opening curly brace '''array''' within square bracket @(At-sign) closing curly brace

| '''Dollar''' opening curly brace array within square bracket one closing curly brace

|This line of code displays the second '''element''' of the '''array'''

|  '''Operating_systems '''is declared with the elements '''Ubuntu, Fedora, Redhat '''and''' Suse'''

| Here, '''array operating_systems''' is passed to the '''function''' '''array_display'.'''

| The syntax to pass an '''array''' to a '''function''' is '''function_name''' space '''dollar''' opening curly brace '''array_name''' within square bracket '''@(At sign)''' closing curly brace

| Similarly, '''colors''' is declared with the '''elements''' '''White, green, red '''and''' blue'''

|Here, '''array colors''' is passed to the '''function''' '''array_display'''

| Now let's save the file and go to the '''terminal'''.

| Type '''chmod space plus x space function underscore array dot sh'''

|Press '''Enter.'''

 

| Type '''dot slash function underscore array dot sh'''

|And the '''second array element''' of ''''operating_systems'''' and ''''colors'''' are also displayed.

| In '''Bash''', ''''exit' '''and''' 'return' statements '''gives status code of a '''function''' or a program.

|The '''return''' statement will return to the script from where it was called.

|'''exit '''statement will end the entire script from where it is encountered.

| Let me open a file ''''return_exit.sh''''

| Function name is '''return_(Underscore)function '''

| Open curly brace opens the '''function definition.'''

| This '''if statement '''compares two variables.

|If the two variables are equal, then commands in ''''if'''' are executed.

| This '''echo statement '''displays the message

|'''This is return function.'''

| '''return 0 '''moves the control from '''function''' to main program with status code 0(zero).

| '''fi''' indicates the end of '''if statement'''

| Here the '''function '''name is''' exit_(Undescore)function '''

| The '''if statement '''here compares two variables.

| If the two variables are equal, then the commands in ''''if'''' are executed.

| This '''echo statement '''displays the message '''"This is exit function"'''

| '''fi''' indicates the end of this '''if statement.'''

| This displays the message '''"We are in main program"'''

| This '''echo statement '''displays the message '''"This line is not displayed"'''

| Save the file and go to the '''terminal.'''

| Type '''chmod space plus x space return underscore exit dot sh'''

|Type '''dot slash return underscore exit dot sh'''

| The output displays the messages as shown.

|The control will be in main program, which is the script itself.

| As the two variables are equal, it displays the message '"This is return function'''

| Then it encounters '''return 0.'''And the control flows from '''function''' to the statement below the '''function call, '''in the main program.

| Then it displays the message '''We are in main program'''

| After that, the control goes to '''exit_function''' because of the '''function call'''.

|As the two variables are equal, it displays the message '''"This is exit function"'''

| Also, the statement '''This line is not displayed''' will not be executed.

|Let us now summarise.

| In this tutorial, we learnt

| Use of''' exit''' statement in a '''function'''

| Use of '''return''' statement in a '''function'''

|With the help of some examples  

| As an assignment.

 

|-

|Write a program,

|  Where a '''function '''adds all the elements in an '''array'''  The '''function''' should display the sum of elements.

|Make 2 '''function''' '''calls''' with '''array elements''' (1, 2, 3) and (4, 5, 6)

| Watch the video available at the link shown below. http://spoken-tutorial.org /What\_is\_a\_Spoken\_Tutorial

|It summarises the Spoken Tutorial project.

| The Spoken Tutorial Project Team

| Conducts workshops using spoken tutorials Gives certificates to those who pass an online test For more details, please write to contact@spoken-tutorial.org

| 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.More information on this Mission is available at the link shown below http://spoken-tutorial.org\NMEICT-Intro

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