Chandrika: Created page with ''''Title of script''': Method Overloading '''Author: '''Prathamesh Salunke '''Keywords: '''video tutorial, method, overloading {| style="border-spacing:0;" ! Visual …'

2012-11-27T10:20:15Z

Created page with ''''Title of script''': Method Overloading '''Author: '''Prathamesh Salunke '''Keywords: '''video tutorial, method, overloading {| style="border-spacing:0;" ! <center>Visual …'

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'''Title of script''': Method Overloading

'''Author: '''Prathamesh Salunke

'''Keywords: '''video tutorial, method, 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 '''method 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 '''method overloading.'''

- To overload '''method.'''

|-
| 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 '''methods '''and

to '''overload''' '''constructor''' 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

'''Method 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 two or more methods with same name within a class.

They must differ in number or types of parameters.

These methods are called '''overloaded methods'''.

The process is called '''method''' '''overloading'''.

|-
| 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'''

'''int a = 10;'''

'''int b = 5;'''
| 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 '''method'''.

In '''eclipse''', I have a class '''Addition.'''

Let us declare two integer variables.

So typre '''''int''''' '''''a''''' ''is equalto '''10''' and '''int''' '''b''' is equalto '''5''.'''

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

'''void add()'''

'''{'''

'''System.out.println(a+b);'''

'''}'''
| 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 create a method to add these two integers.

So type''''' void add '''parentheses''.

''Within curly brackets '''System''' dot '''out''' dot '''println'''.''

''Within parentheses '''a+b'''.''

So this method will give us the sum of two integers.

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

'''void addTwoNumbers(int num1,int num2)'''

'''{'''

'''System.out.println(num1, num2);'''

'''}'''
| 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 create a method that takes two numeric arguments.

The method prints the sum of two numbers.

So type '''''void addTwoNumbers'''''.

''Within parentheses '''int''' '''num1''' comma '''int''' '''num2.'''''

''Within curly brackets '''System''' dot '''out''' dot '''println''' '''num1''' plus '''num2.'''''

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

'''Addition obj = new Addition();'''

'''obj.add();'''

'''obj.addTwoNumbers(2.5,3.5);'''
| 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 create an object of the class and call the methods.

So in '''Main''' type '''''Addition''''' '''''obj''' is equalto '''new''' '''Addition''' parentheses.''

'''''Obj.add''' parentheses'''.'''''

'''''Obj.addTwonumbers''' parentheses.''

Within parentheses we have to pass integer arguments.

Suppose if we pass floating point values.

So type '''2.5''' comma and integer '''3'''.

|-
| 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 '''method addTwoNumbers double, double is undefined'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''addTwoNumbers(double num1,double num2)'''
| 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 what we do is in the method instead of int we will give double.

So instead of '''''int''''' type '''''double'''''

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| '''Point to addTwoNumbers(2.5,3.5);'''
| 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 we see that the error is resolved.

And as we know that Java automatically i.e. implicitly coverts int to double.

So here we can pass integer arguments as well.

|-
| 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;"| In the output we see the sum of two integers we declared.

And the sum of two numeric arguments that we passed.

|-
| 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 methods
| 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 we see that both the method perfroms same operation.

The difference is that first method takes no parameter. While the other method takes two parameters.

So in such case java provides us with '''method''' '''overloading'''.

|-
| style="border-top:none;border-bottom:0.035cm solid #000000;border-left:0.035cm solid #000000;border-right:none;padding:0.097cm;"| Replace addTwoNumbers with add
| 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 what we do is give same name to both the methods.

So replace '''''addTwoNumbers''''' with '''''add'''''.

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

void add(double n1,double n2,double n3)

Highlight

void add(double n1,double n2,double n3)
| 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 will define one more method with same opearation.

So type '''''void''' '''add'''.''

''Within parentheses '''double n1 '''comma '''double n2''' comma '''double n3.'''''

So we gave three parameters to the method.

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

System.out.println(n1+n2+n3);

}
| 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;"| ''Within curly brackets '''System''' dot '''out''' dot''' println'''.''

''Within parentheses '''n1''' plus '''n2''' plus '''n3'''.''

So this method will give sum of three numbers.

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

obj.add(1,5,6);
| 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 method.

So type '''''add''' within parentheses '''1''' comma''' 5''' comma '''6'''''

|-
| 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;"| So in the output we see the sum of three number as well.

Java compiler overloads the proper method depending on the parameters.

It checks the number and type of parameters.

So as a programmer we dont have worry about the method name.

Or even the type or number of argument passed.

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

void add(String s1,String s2)

{

System.out.println(s1+s2);

}
| 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 create one more overload method which append strings.

So type '''''void add.'''''

''Within parentheses '''String''' '''s1''' comma '''String''' '''s2'''. ''

''Within curly brackets '''System''' dot '''out''' dot '''println'''.''

''Within parentheses '''s1''' plus '''s2'''.''

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

obj.add(“Hello ”,“World”);
| 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 call the method.

So type '''''obj''' dot '''add'''.''

''Within parentheses in double quotes '''Hello''' comma in double quotes space '''World'''.''

|-
| 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;"| So in the output we see '''Hello''' space '''World'''.

So the add method with two string arguments, appends the string.

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

int add(){}
| 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;"| Suppose now we declare add method with return type.

So type'' '''int''' '''add''' parentheses curly brackets.''

|-
| 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

Remove int add(){}
| 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 get an error that '''it's a duplicate method.'''

This is because we have already defined a method add with no parameters.

So remember that to overload method the parameters must differ.

Having different return types will not overload the method.

So remove this part and Save the file.

This is how '''method 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;"| Summary 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;"| So in this tutorial we learnt,

- About '''method overloading.'''

- To''' overload method.'''

- Advantage of '''method overloading.'''

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

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 overload methods 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

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

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 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/Method-overloading/English - Revision history

Chandrika: Created page with ''''Title of script''': Method Overloading '''Author: '''Prathamesh Salunke '''Keywords: '''video tutorial, method, overloading {| style="border-spacing:0;" ! Visual …'