Difference between revisions of "Java/C2/Default-constructor/English-timed"

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|  Welcome to the Spoken Tutorial on '''default''' '''constructor''' in''' java'''.
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|  Welcome to the Spoken Tutorial on '''Default constructor''' in''' java'''.
  
 
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|  00:10
 
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| About the default constructor.   
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| About the default constructor.   
  
 
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|  00:12
 
|  00:12
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| And  to create a constructor.  
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|And  to create a constructor.  
  
 
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|  00:15
 
|  00:15
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|   Here we are using  
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| Here we are using:
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* Ubuntu version 11.10  
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'''Ubuntu version 11.10'''
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* Java Development Environment jdk 1.6 and  
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'''Java Development Environment jdk 1.6''' and  
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*  Eclipse 3.7.0
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'''Eclipse 3.7.0'''
  
 
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| If not, for relevant tutorials please visit our website which is as shown.
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| If not, for relevant tutorials, please visit our website which is as shown.http://www.spoken-tutorial.org  
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http://www.spoken-tutorial.org  
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|  00:42
 
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|  '''Constructor''' is used to initialize the instance variables.
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|  '''Constructor''' is used to initialize the '''instance''' variables.
  
 
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|  Let us now see how '''constructor''' is defined in java.
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|  Let us now see how a '''constructor''' is defined in java.
  
 
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| So in the '''eclipse,''' I have already created a java file, '''Student.java'''.
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| So, in the '''eclipse''', I have already created a java file '''Student.java'''.
  
 
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| Within curly brackets, type: '''System''' dot '''out''' dot '''println''' '''roll_number'''
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| Within curly brackets, type: '''System''' dot '''out''' dot '''println''' '''roll_number;'''
  
 
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| Then '''System''' dot '''out''' dot '''println''' '''name'''.
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| Then '''System''' dot '''out''' dot '''println''' '''name;'''.
  
 
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|02:03   
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|  Now in '''Main''' '''method''' we will call this method.
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|  Now in '''main''' '''method''' we will call this method.
  
 
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| So type '''Student''' object name '''stu''' equal to '''new''' '''Student'''.
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| So, type: '''Student''' object name '''stu''' equal to '''new''' '''Student()'''.
  
 
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|   We see the output zero and null.
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| We see the output 'zero' and 'null'.
  
 
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| So, the '''int''' variable '''roll_number''' has been initialized to its default value zero.
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| So, the '''int''' variable '''roll_number''' has been initialized to its default value 'zero'.
  
 
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| And the '''String''' '''name''' has been initialized to its default value null.
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| And the '''String''' '''name''' has been initialized to its default value 'null'.
  
 
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| So, type: '''Student''' parenthesis and curly brackets.
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| So, type: '''Student''' S capital parenthesis and curly brackets.
  
 
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| Remember the '''Constructor''' has the same name as the class name to which it belongs.
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| Remember, the '''Constructor''' has the same name as the 'class name' to which it belongs.
  
 
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| 03:38
 
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|  '''Constructors''' are also similar to '''method'''s but there are some important differences.
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|  Constructors are also similar to '''methods''' but there are some important differences.
  
 
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| But here no default '''constructor''' is created because we have defined a '''constructor.'''
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| But here, no default '''constructor''' is created because we have defined a '''constructor.'''
  
 
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|  We see in the output that the '''roll_number''' value is '''ten''' and '''name''' is Raman.
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|  We see in the output that the '''roll_number''' is '''ten''' and the '''name''' is Raman.
  
 
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|  Now, let us see some difference between  '''method''' and a '''constructor'''.
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|  Now, let us see some differences between  '''method''' and a '''constructor'''.
  
 
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|* About the default '''constructor'''.
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|About the default '''constructor'''.
 
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|  05:34
 
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|* To define a '''constructor'''.
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|To define a '''constructor'''.
 
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|* And Differences between '''method''' and '''constructor.'''
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|And Differences between '''method''' and '''constructor.'''
  
 
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|  05:41
 
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|  For self assessment,  
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|  For self assessment, create a '''class''' '''Employee''' with variables and a  '''method''' to display variables.
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|  05:42
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| create a '''class''' '''Employee''' with variables and a  '''method''' to display variables.
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|  To know more about the Spoken Tutorial Project
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|  To know more about the Spoken Tutorial Project,
 
|-
 
|-
 
|  05:54
 
|  05:54
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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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|  06:29
 
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| More information on this mission is available at:  
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| More information on this mission is available at: http://spoken-tutorial.org/NMEICT-Intro.
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[http://spoken-tutorial.org/NMEICT-Intro]
+
  
 
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Latest revision as of 15:27, 28 March 2017

Time Narration
00:02 Welcome to the Spoken Tutorial on Default constructor in java.
00:07 In this tutorial, we will learn:
00:10 About the default constructor.
00:12 And to create a constructor.
00:15 Here we are using:

Ubuntu version 11.10 Java Development Environment jdk 1.6 and Eclipse 3.7.0

00:26 To follow this tutorial, you must know
00:29 how to create a class and the object of the class in java using eclipse.
00:34 If not, for relevant tutorials, please visit our website which is as shown.http://www.spoken-tutorial.org
00:42 Constructor is used to initialize the instance variables.
00:46 It is called at the creation of new object.
00:50 Let us now see how a constructor is defined in java.
00:55 So, in the eclipse, I have already created a java file Student.java.
01:02 In the Student class we will declare two variables.
01:07 So type int roll_number semi-colon and String name semicolon.
01:20 Now let us create a method.
01:22 So, type: void studentDetail().
01:33 Within curly brackets, type: System dot out dot println roll_number;
01:50 Then System dot out dot println name;.
02:03 Now in main method we will call this method.
02:08 So, let us create an object and call the method.
02:14 So, type: Student object name stu equal to new Student().
02:28 Then stu dot method name i.e studentDetail.
02:41 Save and Run the program.
02:46 We see the output 'zero' and 'null'.
02:49 So, the int variable roll_number has been initialized to its default value 'zero'.
02:56 And the String name has been initialized to its default value 'null'.
03:02 If we do not define a constructor then a default constructor is created.
03:08 Default constructor has no parameters.
03:11 It initializes the instance variables to their default value.
03:16 Now let us define a constructor.
03:18 So, type: Student S capital parenthesis and curly brackets.
03:30 Remember, the Constructor has the same name as the 'class name' to which it belongs.
03:38 Constructors are also similar to methods but there are some important differences.
03:44 Save and Run the program.
03:48 We see the same output.
03:51 This is because the constructor that we defined is same as having no constructor.
03:58 But here, no default constructor is created because we have defined a constructor.
04:06 Now, let's give values to our variables.
04:11 So, inside the constructor type: roll_number equal to ten semicolon.
04:25 And name equal to within double quotes Raman.
04:35 Now Save and Run the program.
04:43 We see in the output that the roll_number is ten and the name is Raman.
04:50 So, the constructor initializes the instance field.
04:55 Now, let us see some differences between method and a constructor.
05:01 Constructor does not have a return type.
05:05 whereas method has a return type.
05:10 Constructor is called using the new operator.
05:16 whereas the method is called using the dot operator.
05:21 So, these were some differences between constructor and method.
05:29 So, in this tutorial, we have learnt:
05:32 About the default constructor.
05:34 To define a constructor.
05:36 And Differences between method and constructor.
05:41 For self assessment, create a class Employee with variables and a method to display variables.
05:47 And create a constructor for the class Employee.
05:52 To know more about the Spoken Tutorial Project,
05:54 watch the video available at http://spoken-tutorial.org/What_is_a_Spoken_Tutorial.
06:00 It summarizes the Spoken Tutorial project.
06:03 If you do not have good bandwidth, you can download and watch it.
06:06 The Spoken Tutorial project team:
06:08 Conducts workshops using spoken tutorials.
06:11 Gives certificates to those who pass an online test.
06:14 For more details, please write to contact@spoken-tutorial.org
06:20 Spoken Tutorial project is a part of the Talk to a Teacher project.
06:24 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
06:29 More information on this mission is available at: http://spoken-tutorial.org/NMEICT-Intro.
06:38 This brings us to the end of the tutorial.
06:40 Thanks for joining.
06:42 This is Prathamesh Salunke, signing off. Jai Hind.

Contributors and Content Editors

Gaurav, PoojaMoolya, Sandhya.np14, Sneha

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