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

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|  In the project, I have created a java class name '''MethodDemo'''.
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|  In the project, I have created a java class named '''MethodDemo'''.
  
 
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|  So, inside the  '''Main''' method,  we will  create an object of the '''class''' '''MethodDemo'''.
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|  So, inside the  '''main''' method,  we will  create an object of the '''class''' '''MethodDemo'''.
  
 
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|  So, we have created an object '''md''' of the class '''MethodDemo''' using the '''New''' operator.
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|  So, we have created an object '''md''' of the class '''MethodDemo''' using the '''new''' operator.
  
 
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| Now let us call the method '''displayMessage.'''
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| Now, let us call the method '''displayMessage.'''
  
 
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| So, type: '''md''' dot '''displayMessage'''.   
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| So, type: '''md''' dot '''displayMessage();'''.   
  
 
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|  The '''dot''' operator is used to '''call''' the '''method'''.
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|  The 'dot' operator is used to '''call''' the '''method'''.
  
 
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|  By default it is '''private''', that is accessible only within the class where it is written.
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|  By default, it is '''private''', that is accessible only within the class where it is written.
  
 
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|  Now, inside the method type '''return''' seven semicolon.
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|  Now, inside the method, type '''return''' seven semicolon.
  
 
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| Remember that we write  the '''return'''  statement  at the end of all statements in the method.
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| Remember that we write  the '''return'''  statement  at the end of all statements in the '''method'''.
  
 
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| Now, inside the '''Main''' method, at the end, type the 'print' statement.
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| Now, inside the '''main''' method, at the end, type the 'print' statement.
  
 
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|  This will print the return value of the method.
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|  This will print the '''return''' value of the method.
  
 
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| Now we will write another method and call this methd in '''displayMessage.'''
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| Now we will write another method and call this method in '''displayMessage.'''
  
 
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| | Here we are giving '''int a''' as a parameter to our method.
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| | Here, we are giving '''int a''' as a parameter to our method.
  
 
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|  So we have written a '''square''' method.
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|  So, we have written a '''square''' method
  
 
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|  That will display a square of an integer which is  given as a parameter.
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|  that will display a square of an integer which is  given as a parameter.
  
 
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|  The starting point is the '''Main''' '''method'''.
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|  The starting point is the '''main''' '''method'''.
  
 
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|  So the control goes to the '''displayMessage.'''
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|  So, the control goes to the '''displayMessage'''
  
 
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|  And all the statements in the '''displayMessage''' are executed.  
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|  and all the statements in the '''displayMessage''' are executed.  
  
 
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| Then the control jumps back to the '''Main'''  function.
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| Then the control jumps back to the '''main'''  function.
  
 
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|    We see that we cannot call a non static method inside the '''static'''  method.
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|    We see that we cannot call a 'non static' method inside the '''static'''  method.
  
 
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| So we will '''comment''' this '''call'''.
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| So, we will '''comment''' this '''call'''.
  
 
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| Since '''Main''' is a static method, we can call the '''static  displayMessage '''inside this.
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| Since '''main''' is a static method, we can call the '''static  displayMessage '''inside this.
  
 
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|  Now for '''static method''', we do not need to create  an  object.
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|  Now, for '''static method''', we do not need to create  an  object.
  
 
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|  So we will '''comment''' this object creation.
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|  So, we will '''comment''' this object creation.
  
 
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| We can also call method from other class.
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| We can also call '''method''' from other '''class'''.
  
 
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|  This is how '''method'''s are used in java.
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|  This is how '''methods''' are used in java.
  
 
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|  watch the video available at [http://spoken-tutorial.org/What_is_a_Spoken_Tutorial]  
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|  watch the video available at [http://spoken-tutorial.org/What_is_a_Spoken_Tutorial].
 
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|11:18
 
|  More information on this mission is available at  
 
|  More information on this mission is available at  
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[http://spoken-tutorial.org/NMEICT-Intro]  
+
[http://spoken-tutorial.org/NMEICT-Intro].
  
 
|-
 
|-

Revision as of 18:18, 7 April 2015

Time Narration
00:02 Welcome to the Spoken Tutorial on methods in java.
00:06 In this tutorial, we will learn:
00:08 * To create a method.
00:10 * And to call a method.
00:13 Here we are using,
00:14 * Ubuntu version 11.10
00:17 * Java Development kit 1.6 and
00:20 * Eclipse 3.7.0
00:24 To follow this tutorial, you must know how to write, compile and run a simple java program in eclipse.
00:32 If not, for relevant tutorials, please visit our website which is as shown.

http://www.spoken-tutorial.org

00:40 A java method is a collection of statements that performs a specified operation.
00:46 Let us now write a method.
00:50 So, in the eclipse, I have already created a project Methods.
00:57 In the project, I have created a java class named MethodDemo.
01:06 In the class, outside the main method, we will write a method.
01:13 So, type: void name of the method
01:19 Let us name it as displayMessage parentheses Enter.
01:29 And curly brackets.
01:32 A method can return a value.
01:34 But if you don’t want the method to return a value then the keyword void is used.
01:42 Alright, now inside the curly brackets, let us print a message.
01:47 So, type: System dot out dot println Hello Method.
02:06 So, we have written a method.
02:10 Now, we will call this method.
02:13 So, inside the main method, we will create an object of the class MethodDemo.
02:21 So, MethodDemo object name.
02:26 Let's name it as md =new MethodDemo parentheses semicolon.
02:37 So, we have created an object md of the class MethodDemo using the new operator.
02:48 Now, let us call the method displayMessage.
02:51 So, type: md dot displayMessage();.
03:00 The 'dot' operator is used to call the method.
03:06 Now, let us Run this application by clicking on Run icon.
03:14 We see the output Hello Method on the console.
03:20 Now, let us return an integer instead of void.
03:26 So, type: int.
03:32 Also, make the method public, that is accessible everywhere.
03:37 By default, it is private, that is accessible only within the class where it is written.
03:45 Now, inside the method, type return seven semicolon.
03:55 Remember that we write the return statement at the end of all statements in the method.
04:02 This is because after return statement no other statements are executed.
04:08 Now, inside the main method, at the end, type the 'print' statement.
04:15 So, type: System dot out dot println();
04:23 Within parentheses, we will call the method.
04:28 So, put md dot method inside the parentheses, remove the semicolon.
04:37 This will print the return value of the method.
04:42 Run the application.
04:45 We see in the output, the value 7 is printed.
04:51 Now we will write another method and call this method in displayMessage.
04:59 So, type: public void method name square within parentheses int a.
05:15 Here, we are giving int a as a parameter to our method.
05:20 Now, within curly brackets type: System dot out dot println within parentheses a into a.
05:37 So, we have written a square method
05:40 that will display a square of an integer which is given as a parameter.
05:48 Let us call this method in the displayMessage method.
05:53 So, type: square within parentheses an integer 5 semicolon.
06:07 Run this application.
06:12 We see that the output displays the square of 5 that is 25.
06:19 Now, let us understand the flow of the application.
06:24 The starting point is the main method.
06:29 In the Main method, we have first called the displayMessage.
06:34 So, the control goes to the displayMessage
06:40 and all the statements in the displayMessage are executed.
06:45 The first one is the print statement.
06:50 Then it comes across the square method.
06:54 So the control jumps to the square method.
06:57 The square method takes an integer 5 and returns the square of the integer i.e. 25.
07:06 Then the control goes back to the displayMessage.
07:10 And it returns the value 7.
07:14 Then the control jumps back to the main function.
07:20 Since there are no statements left to execute, in the main method, the application terminates.
07:29 Alright! Now let us make displayMessage as static.
07:35 So, after public type static.
07:40 We see that we cannot call a 'non static' method inside the static method.
07:47 So, we will comment this call.
07:52 Since main is a static method, we can call the static displayMessage inside this.
08:02 Now, for static method, we do not need to create an object.
08:07 So, we will comment this object creation.
08:11 Also we will delete md.
08:18 Run the application.
08:22 We see the output Hello Method and 7.
08:27 We do not see 25 because we have commented the call to square method.
08:34 We can also call method from other class.
08:38 For that, I have created a class Demo.
08:45 Inside the class, create a method.
08:48 So, type: public void show parentheses Enter.
08:56 Inside curly brackets, System dot out dot println
09:07 I am from other class.
09:13 Save the file.
09:16 Go back to MethodDemo class.
09:19 Now we will call this show method, inside the method MethodDemo class.
09:28 For that we need to create the object of the class Demo.
09:22 This is because the show method belongs to the class Demo.
09:38 So, type: Demo d=new Demo parentheses semicolon.
09:48 Then call the method show.
09:54 Lets Run this application.
09:58 We see on the console: I am from other class.
10:04 This is how methods are used in java.
10:09 The method name and the parameters form the signature of the method
10:14 while the curly brackets and the statements form the body of the method.
10:23 So, in this tutorial, we have learnt:
10:25 * To create a method
10:27 * To call a method
10:29 * And different signatures of methods.
10:32 For self assessment, create a method which prints the cube of an integer.
10:38 To know more about the Spoken Tutorial project,
10:41 watch the video available at [1].
10:47 It summarizes the Spoken Tutorial project.
10:50 If you do not have good bandwidth, you can download and watch it.
10:54 The Spoken Tutorial project team:
10:56 Conducts workshops using spoken tutorials.
10:58 Gives certificates to those who have passed an online test.
11:02 For more details, please write to contact@spoken-tutorial.org
11:08 Spoken Tutorial project is a part of the Talk to a Teacher project.
11:12 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
11:18 More information on this mission is available at

[2].

11:27 We have come to the end of this tutorial.
11:29 Thanks for joining.
11:30 This is Prathamesh Salunke, signing off.

Jai Hind.

Contributors and Content Editors

Arya Ratish, Gaurav, Jyotisolanki, PoojaMoolya, Priyacst, Sandhya.np14, Sneha

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