Difference between revisions of "Java/C2/Methods/English-timed"

| Welcome to the Spoken Tutorial on '''methods''' in  java.

| In this tutorial, we will learn:

|* To create a '''method'''.   

|* And to '''call''' a '''method'''.  

|  Here we are using,

|* '''Ubuntu version 11.10'''

|* '''Java Development kit 1.6''' and

|* '''Eclipse 3.7.0'''

|  To follow this tutorial, you must know how to write, compile and run a simple java program in '''eclipse'''.

|  If not, for relevant tutorials, please visit our website which is as shown.

http://www.spoken-tutorial.org  

|A java '''method''' is a collection of statements that performs a specified operation.

|Let us now write a '''method'''.

|  So, in the '''eclipse,''' I have already created a project '''Methods'''.

| In the project, I have created a java class name '''MethodDemo'''.

| In the '''class''', outside the '''main method''', we will write a '''method'''.

|  So, type: '''void''' name of the '''method'''

|  Let us name it as '''displayMessage''' parentheses '''Enter'''.

|  And curly brackets.

| A '''method''' can  return a value.

|  But if you don’t want the method to return a value then the keyword '''void''' is used.

| Alright, now inside the curly brackets, let us print a message.

|  So, type: '''System '''dot''' out '''dot '''println Hello Method'''.  

|  So, we have written a '''method'''.

|Now, we will '''call''' this '''method'''.

|  So, inside the  '''Main''' method,  we will  create an object of the '''class''' '''MethodDemo'''.

|  So, '''MethodDemo''' object name.

|  Let's name it as '''md =new ''' '''MethodDemo''' parentheses semicolon.  

|  So, we have created an object '''md''' of the class '''MethodDemo''' using the '''New''' operator.

| So, type: '''md''' dot '''displayMessage'''.  

|  The '''dot''' operator is used to '''call''' the '''method'''.

| Now, let us '''Run''' this application by clicking on '''Run''' icon.

| We see the output '''Hello Method '''on the '''console'''.

|Now, let us return an '''integer ''' instead of '''void'''.

|  So, type: '''int'''.

|  Also, make the method '''public''', that is accessible everywhere.

|  Now, inside the method type '''return''' seven semicolon.

| Now, inside the '''Main''' method, at the end, type the 'print' statement.

|  So, type: '''System''' dot '''out''' dot '''println();'''

|  Within parentheses, we will '''call''' the '''method'''.

|  So, put '''md''' dot '''method''' inside the parentheses, remove the semicolon.

|  So, type: '''public void ''' method name '''square ''' within parentheses '''int a'''.

| Now, within curly brackets type: '''System '''dot '''out '''dot '''println''' within parentheses '''a''' into '''a'''.

|  So, type: '''square''' within parentheses an integer '''5''' semicolon.

| Now, let us understand the flow of the application.

|  The starting point is the '''Main''' '''method'''.

|  Since there are no statements left to execute, in the '''main''' method, the application terminates.

| Alright! Now let us  make '''displayMessage''' as '''static'''.

|  So, after '''public''' type '''static.'''

|    We see that we cannot call a non static method inside the '''static'''  method.

| So we will '''comment''' this '''call'''.

| Since '''Main''' is a static method, we can call the '''static  displayMessage '''inside this.

|  Now for '''static method''', we do not need to create  an  object.

|  So we will '''comment''' this object creation.

|  Also  we will delete '''md.'''

|  We do not see  25 because we have commented the call to '''square''' method.

| For that, I have created a class '''Demo.'''

|  Inside the '''class''', create a '''method'''.

|  So, type: '''public void show''' parentheses '''Enter'''.

|Inside curly brackets, '''System '''dot''' out '''dot''' println'''

| '''I am from other class.'''

| Go back to '''MethodDemo''' class.

| Now we will '''call''' this '''show''' method, inside the method '''MethodDemo''' class.

|  So, type: '''Demo d=new Demo''' parentheses semicolon.

|  We see on the console: '''I am from other class'''.

|  This is how '''method'''s are used in java.

|  The '''method''' name and the parameters form the signature of the '''method'''

|  while the curly brackets and the statements form the body of the '''method'''.  

|  So, in this tutorial, we have learnt:

|* To create a '''method'''

|* To call a '''method'''

|* And different signatures of '''methods'''.

|  | For self assessment, create a '''method''' which prints the cube of an integer.

| To know more about the Spoken Tutorial Project,

|  Watch the video available at [http://spoken-tutorial.org/What_is_a_Spoken_Tutorial]  

|  It  summarizes the Spoken Tutorial project.

|  If you do not have good bandwidth, you can download and watch it.

|  The Spoken Tutorial project team:

|  Conducts workshops using spoken tutorials.

| Gives certificates to those who have passed an online test.

|  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  

[http://spoken-tutorial.org/NMEICT-Intro]  

|  This is Prathamesh Salunke, signing off.