Chandrika: Created page with ''''Title of script''': Constructor overloading '''Author: '''Prathamesh Salunke '''Keywords: '''video''' '''tutorial,''' '''constructor,''' '''overloading {| style="border-s…'

2012-11-27T10:19:26Z

Created page with ''''Title of script''': Constructor overloading '''Author: '''Prathamesh Salunke '''Keywords: '''video''' '''tutorial,''' '''constructor,''' '''overloading {| style="border-s…'

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'''Title of script''': Constructor overloading

'''Author: '''Prathamesh Salunke

'''Keywords: '''video''' '''tutorial,''' '''constructor,''' '''overloading

{| style="border-spacing:0;"
! <center>Visual Cue</center>
! <center>Narration</center>

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 1

Opening slide
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Welcome to the Spoken Tutorial on '''constructor overloading''' in''' java'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 2

Learning Objectives
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| In this tutorial we will learn

- what is '''constructor overloading'''

- To overload '''constructor'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 3

System Requirements
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Here we are using

* Ubuntu version 11.10
* Java Development Environment jdk 1.6
* Eclipse 3.7

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 4

Prerequisites
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| To follow this tutorial you must know

how to create '''constructors''' in '''java''' using '''eclipse'''.

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

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

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 5

'''Constructor Overloading'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Define multiple '''constructors''' which differ in number or types of parameters.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Switch to '''Eclipse'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us now see how to overload '''constructor'''.

In '''eclipse''', I have a class '''Student''' with two variables and a method.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''Student(int number, String the_name) '''

''' { '''

'''roll_number=number; '''

'''name=the_name; '''

''' }'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us first create a '''parameterized constructor.'''

So type, '''''Student '''within''' '''parentheses''' int number '''comma''' String the_name.'''''

''Within''' '''curly''' '''brackets''', roll_number '''is''' '''equal''' '''to''' number.'''''

And''''' name '''is equalto '''the_name'''''

So we have a '''constructor''' with two parameters.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''new Student();'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now let us call the '''constructor'''.

So type '''''new Student '''parentheses semi colon''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Point to the '''Error'''.
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We see an error that the '''constructor''' '''Student''' is not defined.

This is simply because we have defined a '''constructor''' with parameters.

And we are calling a '''constructor''' without parameters.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''Student(22,”Ram”);'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So let us pass '''arguments'''.

Type '''''22''''' ''comma'' ''in double quotes'' '''''Ram'''''.

We see that the error is resolved.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''Student s = new Student(22,”Ram”);'''

'''s.studentDetail();'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us call the method.

So before '''new '''type''' Student s '''''is equal to.''

Then '''''s''''' ''dot''' studentDetail();'''''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Save''' and '''Run'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| '''Save''' and '''Run''' the program.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Point to the '''Output'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We see the output '''22''' and '''Ram.'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''Student()'''

'''{'''

'''roll_number=0;'''

'''name=”-”;'''

'''}'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now''''' '''''let us define a''''' ''default constructor.'''

So type, '''''Student '''parentheses.''

''Within''' '''curly''' '''brackets''' roll_number '''is equal to''' 0.'''''

And''''' name '''is''' '''equal''' '''to''' '''in''' '''double''' '''quotes''' '''hypen.''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Type:

'''Student s2 = new Student();'''

| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So now we can call the '''constructor''' with no parameters.

So type'' '''Student''' '''s1''' is equal to '''new''' '''Student''' parentheses.''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''s2.studentDetail();'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Then''''' s1 '''dot''' studentDetail'''''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Save''' and '''Run'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| '''Save''' and '''Run''' the program.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Point to the '''Output'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We see the output '''zero''' and '''dash''' when '''default''' '''constructor''' is called.

This is '''constructor''' '''overloading'''.

We have two '''constructor''' with difference in parameter.

Both the '''constructor''' obviously have same name.

So depending on the type and number of parameter, the '''constructor''' is called.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''Student s3=new Student(“Raju”,45);'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Let us see the advantage of '''constructor''' overloading.

Suppose when we call a constructor with two parameters.

So type '''''Student s3= new Student();'''''

And suppose if we pass the '''name''' argument first and then the '''roll''' '''number.'''

That is in ''double quotes '''Raju''' comma '''45'''''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Point to the '''Error'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We see an error that '''constructor String comma int is not defined.'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''Student(String the_name, int r_no)'''

'''{'''

'''roll_number=r_no;'''

'''name=the_name;'''

'''}'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So let us define the constructor.

So type '''''Student''' within parentheses '''String''' '''the_name''' comma '''int''' '''r_no'''''

''Within curly bracket, '''roll_number''' is equal to '''r_no.'''''

And'' '''name''' is equal to '''the_name.'''''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Save''' the file
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| '''Save''' the file.

We see that the error is resolved.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''s3.studentDetail();'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| Now call the method.

So type, '''''s3''''' ''dot'' '''''studentDetail.'''''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Save''' and '''Run'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| '''Save''' and '''Run''' the file.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Point to the Output'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We see '''45''' and '''Raju''' on the console.

So here we see that when we call the '''constructor'''.

We do not have to worry about the parameters we are passing.

This is because we have define multiple '''constructor''' with different parameters.

So the proper '''constructor''' is '''overloaded.'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Type:'''

'''Student(int num)'''

'''{'''

'''roll_number=num;'''

'''}'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We can therefore define '''constructor''' which takes only one parameter.

That is '''roll number'''.

So type '''''Student''' within parentheses''' int num'''.''

''Then within curly brackets '''roll_number '''is equalto '''num'''.''

''And '''name''' is equal to in double quotes '''no''' '''name'''.''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Student s4 = new Student(61);

s4.studentDetail();
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So now when we call the '''constructor''' and give one integer argument.

So type '''''Student''''' '''''s4''''' ''is'' ''equalto'' '''''new''''' '''''Student''''' ''within'' ''parentheses'' '''''61'''''

Then '''''s4 '''dot''' studentDetail '''''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Save''' and '''Run''' the program
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| '''Save''' and '''Run''' the program

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Point to the '''Output'''
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So in the output we see '''roll''' '''number''' as '''61''' and '''name''' as '''no''' '''name.'''

As we can see, the proper overloaded '''constructor''' is called when new is executed.

Based upon the parameters specified the proper '''constructor''' is overloaded.

This is how '''constructor''' '''overloading''' is done.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 6

Summary
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| So in this tutorial, we have learnt

What''' '''is '''constructor overloading.'''

How to overload '''constructor.'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 7

Assignment
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| For self assessment, create multiple constructors for class '''Employee'''.

Overload the '''constructor.'''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 8

About Slide
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| To know more about the Spoken Tutorial Project
* Watch the video available at [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]
* It summarizes the Spoken Tutorial project

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

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 9

About Slide

| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| The Spoken Tutorial Project Team

* Conducts workshops using spoken tutorials

* Gives certificates for those who pass an online test

* For more details, please write to contact@spoken-tutorial.org

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Slide 10

Acknowledgment
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| 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 http://spoken-tutorial.org/NMEICT-Intro]

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"|
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:0.035cm solid #000000;padding:0.097cm;"| We have come to the end of this tutorial.

Thanks for joining.

This is Prathamesh Salunke signing off.

Jai Hind.

|}

Java/C2/Constructor-overloading/English - Revision history

Chandrika: Created page with ''''Title of script''': Constructor overloading '''Author: '''Prathamesh Salunke '''Keywords: '''video''' '''tutorial,''' '''constructor,''' '''overloading {| style="border-s…'