Difference between revisions of "Java/C2/Constructor-overloading/English-timed"

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|  01:26
 
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| ''Within''' '''curly''' '''brackets''', type roll_number '''is''' '''equal''' '''to''' number.'''''
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|Within curly brackets, type '''roll_number''' is equal to '''number.'''
  
  
 
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|  01:38
 
|  01:38
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| And''''' name '''is equal to '''the_name'''''
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| And ''' name''' is equal to '''the_name'''
  
  
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|  01:53
 
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| So in '''main method''' type '''''new Student '''parentheses semi colon''
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| So in '''main method''' type '''new Student''' parentheses semi colon
  
 
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|  02:25
 
|  02:25
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| So within parentheses type '''''22''''' ''comma'' ''in double quotes'' '''''Ram'''''.
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| So within parentheses type '''22''' comma in double quotes '''Ram'''.
  
  
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|  02:36
 
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|   Let us call the method.
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|Let us call the method.
  
  
 
|-
 
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|  02:38
 
|  02:38
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| So before '''new '''type''' Student s '''''is equal to''' new student'''.
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| So before '''new ''' type '''Student s''' is equal to '''new student'''.
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|  02:45
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|03:03
 
|03:03
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| Now''''' '''''let us define a''''' ''' constructor''' with no parameter.
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| Now let us define a '''constructor''' with no parameter.
  
  
 
|-
 
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|  03:07
 
|  03:07
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| So type, '''''Student '''parentheses.''
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| So type, '''Student''' parentheses.
  
  
 
|-
 
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|  03:12
 
|  03:12
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| ''Within''' '''curly''' '''brackets''' roll_number '''is equal to''' 0.'''''
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|Within curly brackets '''roll_number''' is equal to''' 0.'''
  
  
 
|-
 
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|  03:21
 
|  03:21
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| And''''' name '''is''' '''equal''' '''to''' '''in''' '''double''' '''quotes''' '''hypen'' that is no name
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| And ''' name is equal to in double quotes hyphen''' that is no name
  
 
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|  04:35
 
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| So type '''''Student s3= new Student();'''''
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| So type '''Student s3= new Student();'''
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+
  
 
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| 05:52
 
| 05:52
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|Then '''Within curly bracket, '''roll_number''' is equal to '''r_no.'''''
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|Then Within curly bracket, '''roll_number''' is equal to '''r_no.'''
  
 
|-
 
|-
 
| 06:05
 
| 06:05
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| And'' '''name''' is equal to '''the_name.'''''
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| And '''name''' is equal to '''the_name.'''
  
 
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| 06:24
 
| 06:24
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| So '''''s3''''' ''dot'' '''''studentDetail.'''''
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| So '''s3''' ''dot'' '''studentDetail.'''
  
 
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|  06:35
 
|  06:35
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|So we see the output'''45''' and '''Raju'''   
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|So we see the output '''45''' and '''Raju'''   
  
 
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| 07:05
 
| 07:05
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| So type '''''Student''' within parentheses''' int num'''.''
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| So type '''Student''' within parentheses '''int num'''.
  
 
|-
 
|-
 
| 07:16
 
| 07:16
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| '' within curly brackets '''roll_number '''is equalto '''num'''.''
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| within curly brackets '''roll_number '''is equalto '''num'''.
  
 
|-
 
|-
 
| 07:25
 
| 07:25
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| ''And '''name''' is equal to  '''no''' '''name'''.''
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| And '''name''' is equal to  '''no''' '''name'''.
  
 
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| 07:43
 
| 07:43
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| So type '''''Student''''' '''''s4''''' ''is'' ''equalto'' '''''new''''' '''''Student'''''  this time we will pass an  single argument. So let us pass '''''61'''''
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| So type '''Student''' '''s4''' ''is'' ''equalto'' '''new''' '''Student'''  this time we will pass an  single argument. So let us pass '''61'''
  
 
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| 08:04
 
| 08:04
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| Then '''''s4 '''dot''' studentDetail '''''
+
| Then '''s4''' dot ''' studentDetail '''
  
 
|-
 
|-

Revision as of 14:30, 23 September 2014


Time Narration
00:03 Welcome to the Spoken Tutorial on constructor overloading in java.
00:08 In this tutorial we will learn


00:10 what is constructor overloading


00:13 And to overload constructor



00:16 Here we are using
  • Ubuntu version 11.10 OS
  • Java Development kit 1.6
  • Eclipse 3.7.0


00:27 To follow this tutorial you must know


00:30 how to create constructors 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 What is constructor overloading?
00:43 Define multiple constructors for a class.
00:46 They must differ in number or types of parameters.
00:50 Let us now see how to overload constructor.


00:54 In eclipse, I have a class Student with two variables and a method.
01:03 Let us first create a parameterized constructor.


01:07 So type, Student within parentheses int number comma String the_name.


01:26 Within curly brackets, type roll_number is equal to number.


01:38 And name is equal to the_name


01:46 So we have a constructor with two parameters.
01:51 let us call this constructor.


01:53 So in main method type new Student parentheses semi colon
02:03 We see an error, it states that constructor Student is undefined.


02:10 This is simply because we have defined a constructor with two parameters.


02:16 And we are calling a constructor without parameters.
02:22 So we need to pass arguments.


02:25 So within parentheses type 22 comma in double quotes Ram.


02:33 We see that the error is resolved.
02:36 Let us call the method.


02:38 So before new type Student s is equal to new student.
02:45 Now using the object s we will call the method studentDetail()
02:53 Save the program and Run.
02:58 We see the output 22 and Ram.
03:03 Now let us define a constructor with no parameter.


03:07 So type, Student parentheses.


03:12 Within curly brackets roll_number is equal to 0.


03:21 And name is equal to in double quotes hyphen that is no name
03:30 So now we can call the constructor with no parameters.


03:35 So type Student s1 is equal to new Student parentheses semicolon.
03:47 This time we see no error, since we have define a constructor without parameter
03:55 Then s1 dot studentDetail.
04:01 Save and Run the program.
04:04 So in the output we see zero and dash when the default constructor is called.


04:11 This is constructor overloading.


04:13 We have two constructor with different parameter.


04:17 Both the constructor obviously have same name.


04:20 So depending on the type and number of parameter, the constructor is called.
04:26 Let us see the advantage of constructor overloading.


04:30 Suppose now call a constructor with two parameters.


04:35 So type Student s3= new Student();
04:51 Now within parentheses, suppose i gave the name argument first and then the roll number.
04:58 let see what happens.
04:59 So in double quotes Raju comma 45
05:08 We see an error which states that the constructor student with the parameter String comma int is undefined.
05:18 So let us define the constructor.
05:22 So type Student within parentheses String the_name comma int r_no
05:42 So over here first parameter is string and the second parameter is int'
05:52 Then Within curly bracket, roll_number is equal to r_no.
06:05 And name is equal to the_name.
06:15 Save the program.
06:18 Now we see that the error is resolved.
06:22 Let us call the method.
06:24 So s3 dot studentDetail.
06:29 Save the program and Run
06:35 So we see the output 45 and Raju
06:40 So here we see that when we call the constructor.
06:43 We do not have to worry about the parameters that we are passing.
06:47 This is simply because we have define multiple constructor with different parameters.
06:54 So the proper constructor is overloaded.
06:57 We can therefore now define a constructor which takes only one parameter.
07:02 That is roll number.
07:05 So type Student within parentheses int num.
07:16 within curly brackets roll_number is equalto num.
07:25 And name is equal to no name.
07:33 Now let us call this constructor
07:43 So type Student s4 is equalto new Student this time we will pass an single argument. So let us pass 61
08:04 Then s4 dot studentDetail
08:10 Save and Run the program
08:14 So in the output we see the roll number as 61 and name as no name.
08:21 As we can see, the proper overloaded constructor is called when new is executed.
08:27 Based upon the parameters specified the proper constructor is overloaded.
08:33 This is how constructor overloading is done.
08:40 So in this tutorial, we have learnt
08:42 About the constructor overloading.
08:45 to overload constructor and the use of constructor overloading
08:50 For self assessment, create multiple constructors for class Employeeand Overload the constructor.



08:58 To know more about the Spoken Tutorial Project
09:00 Watch the video available at http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
09:06 It summarizes the Spoken Tutorial project
09:09 If you do not have good bandwidth, you can download and watch it


09:12 The Spoken Tutorial Project Team
09:15 Conducts workshops using spoken tutorials
09:17 Gives certificates to those who pass an online test
09:20 For more details, please write to contact@spoken-tutorial.org


09:26 Spoken Tutorial Project is a part of the Talk to a Teacher project
09:30 It is supported by the National Mission on Education through ICT, MHRD, Government of India
09:35 More information on this Mission is available at
09:43 This brings us to the end of the tutorial
09:46 Thanks for joining.
09:47 This is Prathamesh Salunke signing off. Jai Hind.

Contributors and Content Editors

Devisenan, Gaurav, PoojaMoolya, Sandhya.np14, Sneha

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