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 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.
06:39	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.
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10:19	We have come to the end of this tutorial.
10:21	Thanks for joining.This is Prathamesh Salunke, signing off. Jai Hind.

Contributors and Content Editors

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