PoojaMoolya at 06:29, 28 February 2017

2017-02-28T06:29:47Z

Pratik kamble at 10:13, 15 July 2014

2014-07-15T10:13:01Z

Krupali at 09:58, 3 October 2013

2013-10-03T09:58:21Z

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Jyotisolanki at 08:43, 4 September 2013

2013-09-04T08:43:52Z

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Jyotisolanki: Created page with '{| border=1 || ''Time''' || '''Narration''' |- | 00:02 | Welcome to the Spoken Tutorial on '''using this keyword''' in '''java'''. |- | 00:07 | In this tutorial we will lea…'

2013-09-04T08:31:42Z

Created page with '{| border=1 || ''Time''' || '''Narration''' |- | 00:02 | Welcome to the Spoken Tutorial on '''using this keyword''' in '''java'''. |- | 00:07 | In this tutorial we will lea…'

New page

{| border=1
|| ''Time'''
|| '''Narration'''

|-
| 00:02
| Welcome to the Spoken Tutorial on '''using this keyword''' in '''java'''.

|-
| 00:07
| In this tutorial we will learn

|-
| 00:09
|About use of '''this''' keyword

|-
| 00:11
| To use '''this''' keyword with '''fields'''

|-
| 00:14
| To use '''this '''keyword for chaining of '''constructors'''.

|-
| 00:17
| Here we are using

* Ubuntu version 11.10
* jdk 1.6
* Eclipse 3.7.0

|-
| 00:28
| To follow this tutorial you must know

|-
| 00:30
| how to create a ''' constructor''' in '''java''' using '''eclipse'''.

|-
| 00:34
| If not, for relevant tutorials please visit our website which is as shown,

('''http'''://'''www.spoken'''-'''tutorial.org''')

|-
| 00:40
|Now we will see the use of this '''key word'''

|-
| 00:44
| Within a '''constructor''', '''this''' is a reference to the current '''object'''.

|-
| 00:48
| We can refer any member of the current '''object''' within a''' constructor''' using '''this'''.

|-
| 00:55
|Now we will see the use of '''this''' keyword with '''fields'''.

|-
| 01:00
| '''this '''keyword helps us to avoid name conflicts.

|-
| 01:07
| We can see such an example here.

|-
| 01:10
| For that let us open '''Eclipse'''.

|-
| 01:17
| Open the '''Student class''' we had created in the earlier tutorial.

|-
| 01:23
| Comment the '''default constructor ''' comment the '''constructor''' with 1 parameter.

|-
| 01:40
| Also comment the code for creating the first two '''objects'''.

|-
| 02:03
| Now, notice the '''parameterized constructor.'''

|-
| 02:11
| '''the_roll_number''' and '''the_name '''are the arguments passed to the constructor.

|-
| 02:20
| '''roll_number''' and '''name '''are the instance variables.

|-
| 02:26
| Now, let me change the arguments to '''roll_number''' and '''name''' itself.

|-
| 02:39
| So inside the '''constructor''' we have:

|-
| 02:42
| '''roll_number '''equal to''' roll_number''' and '''name '''equal to''' name.'''

|-
| 02:55
|Now '''Save '''and '''run '''the file.So press'''Ctrl ,S'''and '''Ctrl, F11'''

|-
| 03:04
| We get the output as follows:

|-
| 03:07
| I am a Parameterized Constructor
''' 0
null'''

|-
| 03:12
| Now come back to the code.

|-
| 03:17
| We see 2 warnings in the code.
|-
| 03:20
| Hover your mouse over the warning symbol.

|-
| 03:23
|We can see '''The assignment to the variable roll_number has no effect.'''

|-
| 03:29
| And '''The assignment to the variable name has no effect.'''

|-
| 03:33
| This is because in the '''constructor roll_number and name''' are '''local variables'''.

|-
| 03:40
| '''Local variables''' are '''variables''' that are accessible within the '''method''' or '''block'''.

|-
| 03:47
| Here, '''roll_number''' and '''name''' will be initialized to '''11''' and '''Raju'''.

|-
| 03:54
| Because we have passed the values '''11''' and '''Raju'''the constructor.

|-
| 04:01
| But once they come out of the '''constructor''', it is not accessible.

|-
| 04:06
| Then the only '''roll_number''' and '''name''' we know are the '''instance variables'''.

|-
| 04:13
| They have been initialized to '''0 '''and '''null '''already once the '''object''' is created.

|-
| 04:18
| So we got the output as '''0 '''and '''null'''.

|-
| 04:21
| Now, let us make a small change inside the constructor.

|-
| 04:29
| So type '''this '''''dot '''''roll_number equal to roll_number'''.

|-
| 04:37
| And''' this '''''dot '''''name equal to name'''.

|-
| 04:44
| Now '''save '''and '''run''' the file. So press '''ctrl, S''' And '''Ctrl, F11''' keys

|-
| 04:51
| We get the output as

|-
| 04:53
| I am Parameterized Constructor
'''11 and
Raju'''

|-
| 04:58
| This is because '''this '''''dot '''''roll_number '''and '''this '''''dot '''''name''' refers to the '''instance variables''' '''roll_number''' and '''name.'''

|-
| 05:12
|And here '''roll_number '''and '''name '''are the arguments passed in the method.

|-
| 05:20
| To avoid confliction between '''local''' and '''instance''' variables we use '''this '''keyword.

|-
| 05:29
| Now we will see the use of '''this keywords''' for chaining of constructor.

|-
| 05:34
| We can use '''this '''keyword inside a '''constructor''' to call another one.

|-
| 05:39
| The '''constructors''' must be in the same '''class.'''

|-
| 05:43
| This is called '''explicit constructor invocation'''.
|-
| 05:46

| So let us come back to the''' Student '''class which we created.

|-
| 05:54
|Now Remove the comments.

|-
| 06:28
| Now comment the part to assign the '''instance variables to their values in the first two constructors.'''

|-
| 06:52
|Then Comment the part which creates the''' '''second and third '''objects.'''

|-
| 07:08
| Now let us first come to the constructor with no parameters.

|-
| 07:16
| After curly brackets type '''this''' within brackets '''11''' and ''semicolon''.

|-
| 07:28
| Inside the second '''constructor''' type '''this''' within brackets '''11''' ''comma'' within double quotes '''Raju''' ''semicolon''.

|-
| 07:42
| Now '''Save''' and '''Run''' the file. So press '''Ctrl,S''' and '''Ctrl , F11'''.

|-
| 07:49
| We get the output as

|-
| 07:51
| '''I am a Parameterized Constructor'''

|-
| 07:54
| '''I am a constructor with a single parameter'''

|-
| 07:57
| '''I am Default Constructor'''

'''11''' and

'''Raju'''

|-
| 08:02
| Now, I will explain the output.

|-
| 08:08
| When the object is created, the respective constructor gets called.

|-
| 08:13
| The '''constructor''' here is the '''no argument constructor'''.

|-
| 08:20
| The control comes to the first line in the '''constructor'''.

|-
| 08:24
| It encounters the '''this '''''within brackets '''''11''' statement.

|-
| 08:26
| Hence it calls the constructor that accepts single integer argument.

|-
| 08:36
| Then the control comes to '''this '''''within brackets''''' 11 '''''comma '''''Raju.'''

|-
| 08:44
| Hence it calls the constructor that accepts 1 '''integer''' and 1 '''String''' argument.

|-
| 08:53
| So this '''constructor''' is executed and we get the output as '''I am Parameterized Constructor'''.

|-
| 09:02
|Now the instance variables will be initialized to '''11''' and '''Raju.'''As we have passed.

|-
| 09:11
| Now, the control goes back to the calling '''constructor'''.

|-
| 09:16
| So the second''' constructor ''' gets executed.

|-
| 09:19
| We get the output as''' I am constructor with a single parameter.'''

|-
| 09:25
| Then, the control goes to the first constructor and executes it.

|-
| 09:30
| So we get output as''' I am a default constructor.'''

|-
| 09:37
| Then '''studentDetail method''' is executed.

|-
| 09:42
| So, we get '''11 '''and '''Raju'''.

|-
| 09:45
| Now, let us make a small change.

|-
| 09:47
| Make the '''this''' statement the last one in the constructor.

|-
| 10:01
| We get a compiler error.

|-
| 10:03
| Hover the mouse over the error symbol.

|-
| 10:06
| We get the error as:

|-
| 10:07
| '''Constructor''' call must be the first statement in the '''constructor'''.

|-
| 10:12
| So we must make it the first line of the '''constructor.'''

|-
| 10:16
| So make it the first line of the '''constructor.'''

|-
| 10:27
| Now we can see that the error has gone.

|-
| 10:31
| So in this tutorial, we learnt

|-
| 10:35
| To use''' this''' keyword with''' fields.'''

|-
| 10:38
| To use''' this''' keyword for chaining '''constructors'''

|-
| 10:41
| How '''this '''keyword should be used within a''' constructor.'''

|-
| 10:45
| For self assessment, in the '''Employee class''' created earlier:

|-
| 10:49
| Create a '''constructor''' with two parameters

|-
| 10:52
| Use''' this '''keyword to initialize the''' instance variables .'''

|-
| 10:57
| Also create a '''constructor''' with 1 and no parameters.

|-
| 11:01
| Try chaining the '''constructors '''using '''this''' as explained in the tutorial.

|-
| 11:07
| To know more about the Spoken Tutorial Project

|-
| 11:09
| Watch the video available at the following link:[http://spoken-tutorial.org/What_is_a_Spoken_Tutorial http://spoken-][http://spoken-tutorial.org/What_is_a_Spoken_Tutorial tutorial.org/What_is_a_Spoken_Tutorial]

|-
| 11:12
| It summarizes the Spoken Tutorial project

|-
| 11:16
| If you do not have good bandwidth, you can download and watch it

|-
| 11:19
| The Spoken Tutorial Project Team

|-
| 11:23
| Conducts workshops using spoken tutorials

|-
| 11:26
| Gives certificates for those who pass an online test

|-
| 11:30
| For more details, please write to contact@spoken-tutorial.org

|-
| 11:36
| Spoken Tutorial Project is a part of the Talk to a Teacher project

|-
| 11:40
| It is supported by the National Mission on Education through ICT, MHRD, Government of India

|-
| 11:46
| More information on this Mission is available at

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

|-
| 11:55
| Thus We have come to the end of this tutorial.

|-
| 11:58
| This is Arya Ratish signing off. Thanks for joining.

@@ Line 1: / Line 1: @@
-−
 {| border=1
 || '''Time'''
@@ Line 27: / Line 27: @@
 | 00:17
 | અહીં આપણે વાપરી રહ્યા છીએ
+'''ઉબુન્ટુ આવૃત્તિ ૧૧.૧૦''' , '''જેડીકે ૧.૬''', '''એક્લીપ્સ ૩.૭.૦'''
-* '''ઉબુન્ટુ આવૃત્તિ ૧૧.૧૦'''
-* '''જેડીકે ૧.૬'''
-* '''એક્લીપ્સ ૩.૭.૦'''
 |-
@@ Line 42: / Line 39: @@
 |-
 | 00:34
-| જો નથી, તો સંદર્ભિત ટ્યુટોરીયલો માટે દર્શાવેલ અમારી વેબસાઈટનો સંદર્ભ લો,
+| જો નથી, તો સંદર્ભિત ટ્યુટોરીયલો માટે દર્શાવેલ અમારી વેબસાઈટનો સંદર્ભ લો, '''(http://www.spoken-tutorial.org)'''
-−
 '''(http://www.spoken-tutorial.org)'''
 |-
@@ Line 202: / Line 197: @@
 | '''I am Parameterized Constructor'''
-'''૧૧''' અને
+'''૧૧''' અને '''Raju'''
-−
- '''Raju'''
 |-
@@ Line 372: / Line 365: @@
 |-
 | 10:06
-| આપણને એરર આપેલ રીતે મળે છે:
+| આપણને એરર આપેલ રીતે મળે છે: '''Constructor call must be the first statement in the constructor'''.
-−
-|-
-| 10:07
-| '''Constructor call must be the first statement in the constructor'''.
 |-
@@ Line 432: / Line 421: @@
 |-
 | 11:09
-| આપેલ લીંક પર ઉપલબ્ધ વિડીયો જુઓ :
+| આપેલ લીંક પર ઉપલબ્ધ વિડીયો જુઓ : '''http://spoken-tutorial.org/What_is_a_Spoken_Tutorial'''
-−
 '''http://spoken-tutorial.org/What_is_a_Spoken_Tutorial'''
 |-
@@ Line 472: / Line 459: @@
 | આ મિશન પર વધુ માહીતી આપેલ લીંક પર ઉપલબ્ધ છે
-* '''http://spoken-tutorial.org/NMEICT-Intro'''
+'''http://spoken-tutorial.org/NMEICT-Intro'''
 |-

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Java/C2/Using-this-keyword/Gujarati - Revision history

PoojaMoolya at 06:29, 28 February 2017

Pratik kamble at 10:13, 15 July 2014

Krupali at 09:58, 3 October 2013

Jyotisolanki at 08:43, 4 September 2013

Jyotisolanki: Created page with '{| border=1 || ''Time''' || '''Narration''' |- | 00:02 | Welcome to the Spoken Tutorial on '''using this keyword''' in '''java'''. |- | 00:07 | In this tutorial we will lea…'