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

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|  00:13
 
|  00:13
 
|  Here we are using:  
 
|  Here we are using:  
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* Ubuntu version 11.10  OS
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* '''Ubuntu version 11.10  OS'''
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* Java Development kit 1.6
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* '''Java Development kit 1.6'''
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* And Eclipse 3.7.0
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* And '''Eclipse 3.7.0'''
  
 
|-
 
|-
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|-
 
|-
 
|  00:42
 
|  00:42
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| Define two or more '''method'''s with same name within a '''class'''.
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| Define two or more '''methods''' with same name within a '''class'''.
  
 
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|-
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|-
 
|-
 
|  01:10
 
|  01:10
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|So, type: '''int''' '''a''' is equal to '''10''' and '''int''' '''b''' is equal to '''5.'''
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|So, type: '''int''' '''a''' equal to '''10''' and '''int''' '''b''' equal to '''5.'''
  
 
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|-
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|-
 
|-
 
|  01:30
 
|  01:30
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|Within curly brackets, type: '''System''' dot '''out''' dot '''println'''.
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|Within curly brackets, type: '''System''' dot '''out''' dot '''println();'''.
  
 
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|-
 
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|  01:55
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|So, type: '''void addTwoNumbers'''.
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|So, type: '''void addTwoNumbers()'''.
 
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|-
 
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|-
 
|-
 
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|  02:44
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|  Let us create an '''object''' of the '''class''' and call the '''method'''s.
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|  Let us create an '''object''' of the '''class''' and call the '''methods'''.
  
 
|-
 
|-
 
|  02:49
 
|  02:49
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|So, in  the  '''Main''' method  type: '''Addition''' i.e the class name  '''obj''' is equal to '''new''' '''Addition''' parentheses semicolon.
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|So, in  the  '''main''' method  type: '''Addition''' i.e the class name  '''obj''' equal to '''new''' '''Addition''' parentheses semicolon.
  
 
|-
 
|-
 
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|  03:13
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|Then '''Obj.add'''   
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|Then '''Obj.add();'''   
  
 
|-
 
|-
 
|  03:18
 
|  03:18
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|And '''Obj.addTwonumbers'''  within parentheses.
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|And '''Obj.addTwonumbers()'''  within parentheses
  
 
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|-
 
| 03:45
 
| 03:45
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|  We get an error which states that: ''' the method addTwoNumbers  int comma int  of the  class addition is not applicable for the arguments double comma int'''.
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|  We get an error. It states that: ''' The method addTwoNumbers  int comma int  of the  class addition is not applicable for the arguments double comma int'''.
  
 
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|-
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|-
 
|  04:12
 
|  04:12
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| we see that the error is resolved.
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| We see that the error is resolved.
  
 
|-
 
|-
 
|  04:17
 
|  04:17
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|  we also  know that Java automatically i.e. implicitly coverts '''int''' into '''double'''.
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|  We also  know that Java automatically i.e. implicitly coverts '''int''' into '''double'''.
  
 
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| 04:43
 
| 04:43
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|  Now we see that both the methods perform same operation.
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|  Now, we see that both the methods perform same operation.
  
 
|-
 
|-
 
|  04:50
 
|  04:50
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|The difference is that the first method  has no parameter while the second method has  parameters.
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|The difference is that the first method  has no parameters while the second method has  parameters.
  
 
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|-
 
|-
 
|  05:09  
 
|  05:09  
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|So, replace '''addTwoNumbers''' with '''add'''; also change here.
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|So, replace '''addTwoNumbers()''' with '''add()''', also change here.
  
 
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|  05:33
 
|  05:33
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|So, type: '''void''' '''add'''.
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|So, type: '''void''' '''add()'''.
  
 
|-
 
|-
 
|  05:38
 
|  05:38
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|And within parentheses '''int n1 '''comma '''int n2''' comma '''int n3.'''
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| Within parentheses '''int n1 '''comma '''int n2''' comma '''int n3.'''
  
 
|-
 
|-
 
|  05:51
 
|  05:51
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|So we have given three parameters.
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|So, we have given three parameters.
  
 
|-
 
|-
 
| 05:54
 
| 05:54
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| Then, within curly brackets '''System''' dot '''out''' dot''' println'''.
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| Then, within curly brackets '''System''' dot '''out''' dot''' println()'''.
  
 
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|-
 
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|  06:19
 
|  06:19
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|So, type: '''obj''' dot '''add''' '''1''' comma''' 5''' comma '''4'''.
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|So, type: '''obj''' dot '''add()''' '''1''' comma''' 5''' comma '''4'''.
  
 
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|-
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|-
 
|  07:29
 
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|Within curly brackets '''System''' dot '''out''' dot '''println'''.
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|Within curly brackets '''System''' dot '''out''' dot '''println()'''.
  
 
|-
 
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|-
 
|-
 
| 07:45
 
| 07:45
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| And we will '''call'''  this '''method'''.
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| Then we will '''call'''  this '''method'''.
  
 
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|  08:40
 
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|  We get an error.  It states that '''duplicate method add''' in type addition.
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|  We get an error.  It states that '''"Duplicate method add() in type Addition"'''.
  
 
|-
 
|-
 
|  08:48
 
|  08:48
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|This is because we have already declared a  method '''add''' with no parameters.
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|This is because we have already declared a  method '''add()''' with no parameters.
  
 
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|    09:25
 
|    09:25
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|For self assessment: create a '''method subtract''' that subtracts number,
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|For self assessment: Create a '''method subtract''' that subtracts number,
  
 
|-
 
|-
 
|09:31   
 
|09:31   
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|overload it.  
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|Overload it.  
  
 
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| watch the video available at [http://spoken-tutorial.org/What_is_a_Spoken_Tutorial]  
+
| watch the video available at [http://spoken-tutorial.org/What_is_a_Spoken_Tutorial].
 
|-
 
|-
 
|  09:42
 
|  09:42

Revision as of 16:56, 8 April 2015


Time Narration
00:01 Welcome to the Spoken Tutorial on method overloading in java.
00:06 In this tutorial we will learn:
00:08 * What is method overloading.
00:10 * And to overload method.
00:13 Here we are using:
  • Ubuntu version 11.10 OS
  • Java Development kit 1.6
  • And Eclipse 3.7.0
00:24 To follow this tutorial, you must know
00:26 how to create methods and
00:29 to overload constructor in java using eclipse.
00:32 If not, for relevant tutorials, please visit our website which is as shown.

http://www.spoken-tutorial.org

00:39 What is method overloading?
00:42 Define two or more methods with same name within a class.
00:46 They must differ in number or types of parameters.
00:50 These methods are called overloaded methods.
00:54 The process is called method overloading.
00:57 Let us now see how to overload a method.
01:00 In eclipse, I have a class Addition.
01:06 Inside the class, we will declare two integer variables.
01:10 So, type: int a equal to 10 and int b equal to 5.
01:19 Let us create a method to add these two integers.
01:23 So, type: void add parentheses.
01:30 Within curly brackets, type: System dot out dot println();.
01:40 Inside parentheses a+b.
01:44 So, this method will give us the sum of two integer variables.
01:50 Let us create another method which takes two parameters.
01:55 So, type: void addTwoNumbers().
02:04 Within parentheses int num1 comma int num2.
02:14 Then, within curly brackets System dot out dot println num1 plus num2.
02:35 So, this method will give us the sum of two values that are passed as arguments to this method.
02:44 Let us create an object of the class and call the methods.
02:49 So, in the main method type: Addition i.e the class name obj equal to new Addition parentheses semicolon.
03:13 Then Obj.add();
03:18 And Obj.addTwonumbers() within parentheses
03:31 we will pass two arguments.
03:33 Suppose if we pass floating point values.
03:37 So, type 2.5 comma and an integer 3.
03:45 We get an error. It states that: The method addTwoNumbers int comma int of the class addition is not applicable for the arguments double comma int.
03:57 So, what we do is, in the method instead of int we will give double.
04:06 So replace int by double . Save the file.
04:12 We see that the error is resolved.
04:17 We also know that Java automatically i.e. implicitly coverts int into double.
04:24 So, here we can pass integer arguments as well.
04:28 Now Save and Run the program.
04:32 In the output, we see the sum of two integer variables
04:37 and the sum of two numeric arguments that we passed.
04:43 Now, we see that both the methods perform same operation.
04:50 The difference is that the first method has no parameters while the second method has parameters.
05:00 So, in such cases java provides us with method overloading.
05:05 So, what we do is, give same name to both the methods.
05:09 So, replace addTwoNumbers() with add(), also change here.
05:29 We will define one more method with same operation.
05:33 So, type: void add().
05:38 Within parentheses int n1 comma int n2 comma int n3.
05:51 So, we have given three parameters.
05:54 Then, within curly brackets System dot out dot println().
06:03 Within parentheses n1 plus n2 plus n3.
06:11 So, this method will give sum of three numbers.
06:17 Let us call this method.
06:19 So, type: obj dot add() 1 comma 5 comma 4.
06:35 Save and Run.
0639 In the output, we see the sum of three number i.e 10.
06:47 So, Java compiler overloads the proper method depending on the parameters.
06:52 It checks the number and type of parameters passed.
06:57 So, as a programmer we don't have to worry about the method name.
07:01 Nor even the type or number of arguments we passed.
07:05 We can create one more method which appends strings.
07:11 So we will create one more overload method.
07:15 Type: void add String s1 comma String s2.
07:29 Within curly brackets System dot out dot println().
07:41 Within parentheses s1 plus s2.
07:45 Then we will call this method.
07:50 So, type: obj dot add.
07:55 Within parentheses in double quotes Hello comma in double quotes space World.
08:07 Now Save and Run the program.
08:12 So, in the output we see Hello space World.
08:16 So, the add method with two string arguments, appends the string.
08:21 Suppose now we declare add method with return type.
08:27 So, type: int add parentheses no parameter and curly brackets.
08:40 We get an error. It states that "Duplicate method add() in type Addition".
08:48 This is because we have already declared a method add() with no parameters.
08:54 So, remember that to overload a method, the parameters must differ.
08:58 Having different return types will not overload the method.
09:03 So, remove this method and Save the file.
09:09 This is how method overloading is done in java.
09:16 So, in this tutorial we learnt:
09:18 * About method overloading.
09:20 * To overload method.
09:22 * And advantage of method overloading.
09:25 For self assessment: Create a method subtract that subtracts number,
09:31 Overload it.
09:33 To know more about the Spoken Tutorial project,
09:36 watch the video available at [1].
09:42 It summarizes the Spoken Tutorial project.
09:45 If you do not have good bandwidth, you can download and watch it.
09:48 The Spoken Tutorial project team:
09:50 Conducts workshops using spoken tutorials.
09:52 Gives certificates to those who pass an online test.
09:56 For more details, please write to contact@spoken-tutorial.org
10:01 Spoken Tutorial Project is a part of the Talk to a Teacher project.
10:05 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:11 More information on this mission is available at

[2].

10:19 We have come to the end of this tutorial.
10:21 Thanks for joining.
10:22 This is Prathamesh Salunke, signing off. Jai Hind.

Contributors and Content Editors

Devisenan, Gaurav, Jyotisolanki, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha

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