Java/C2/Method-overloading/English-timed

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 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 is equalto 10 and int b is equalto 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 parameter.
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 argument to this methods.
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 is equalto new Addition parentheses semicolon.
03:13	ThenObj.add
03:18	AndObj.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 which states that , the method addTwoNumbers int comma int of the class addition is not applicable for the argument double comma int.
03:57	So what we do is in the method instead of int we will give double.
04:06	So replaceintby 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 an integer arguments as well.
04:28	Now Save and Run the program
04:32	In the output we see the sum of two integers variables,
04:37	And the sum of two numeric arguments that we passed.
04:43	Now we see that both the method performs same operation.
04:50	The difference is that the first method has no parameter. While the second method has parameters.
05:00	So in such case 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 opearation.
05:33	So type void add.
05:38	AndWithin 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.e10
06:47	So Java compiler overloads the proper method depending on the parameters.
06:52	It checks the number and type of parameter passed
06:57	So as a programmer we dont have worry about the method name.
07:01	Nor even the type or number of argument we passed.
07:05	We can create one more method which append 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	And 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 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.
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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