Difference between revisions of "BASH/C3/Recursive-function/English-timed"

|  Dear friends, welcome to the spoken tutorial on''' Recursive function.'''

| '''What is a Recursive''' function?

| With the help of some examples  

| 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  

| Please note,''' GNU Bash''' '''version 4''' or above is recommended for practice  

| Let us see what a recursive function is.

| A '''recursive function''' is one which calls itself

|  '''Recursion''' is a useful technique for simplifying complex algorithms

|  Let me open a file named '''factorial.sh'''

|  I have typed the code in this file.

|  '''factorial '''is the function name.  

|  Inside this, we print a message “Inside factorial function”

|  This statement reads user's input and stores the value in variable ''''n''''

|  Here we have '''if-else condition.'''

| '''If '''condition checks whether the value of''' 'n'''' is '''equal to zero.'''

| If '''true, '''it will display the message '''"factorial value of n is 1".'''

|  Here is the '''else '''part of the '''if '''statement.

| It calls the '''factorial function.'''

| And '''fi '''is the end of the '''if-else''' statement.

| Let us run the file''' factorial.sh.'''

| Open the terminal using '''CTRL+ALT+T '''keys simultaneously on your keyboard.

| Type '''dot slash factorial.sh'''

|  We see '''"Enter the number"'''.

| I will enter '''0'''.

|  The output is displayed as:

| '''factorial value of 0 is 1'''

|  Now press the '''uparrow''' key. Recall the previous command.

| This time, I will enter''' 5 '''.

|  Now the output is displayed as:

| '''Inside factorial function.'''

|  Let us add some more logic to the '''factorial function.'''

| Come back to our code.

|  Now let us replace, the '''echo statement''' inside the '''factorial function''' with the code block.

| Click on '''Save'''

|  '''temp '''is a variable and stores the value entered by user.

|  '''If condition''' checks whether the variable value is equal to 1'''.'''

| If '''true''', it will print 1.

| This reduces one from the '''temp '''variable value.

| And stores the result in a variable ''''f'.'''

|  '''Variable f '''stores the output of '''factorial function.'''

|  Value of variable '''f''' and '''temp''' is multiplied and stored in '''f'''.

| Then we print the value of '''f.'''

|  Now come back to our '''slides.'''

| # The value of '''n''' is taken from the user i.e. '''n'''

| # If the value entered is equal to zero, then it prints a message

| # Else it goes to the function '''factorial'''

| # Here, if the value is equal to one, then it prints value as one

| # If not, it makes a '''recursive call''' until the value is equal to one

| # Then, all the values are multiplied and displayed

| Press the '''uparrow''' key.

| Now I will enter''' 5 '''as the input value.

|  We get the '''factorial '''of number 5.

| That is '''120.'''

|  We can see the flow of the program on '''terminal'''. Analyse and trace the flow of the program.

| Come back to our slides.

|  Let us summarise.  

 

| In this tutorial we have learnt,

| With the help of some examples  

|  As an assignment.

 

| Write a program where the '''recursive function''' calculates the sum of''' N '''numbers

| It summarises the Spoken Tutorial project.

|  The Spoken Tutorial Project Team Conducts workshops using spoken tutorials

| 05:53

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| This is Ashwini Patil signing off.