Java/C2/Array-Operations/English-timed

Time	Narration
00:02	Welcome to the spoken tutorial on Array Operations in java.
00:07	In this tutorial, you will learn how to:
00:09	import the class Arrays and
00:12	perform basic operations on arrays.
00:15	For this tutorial, we are using Ubuntu 11.10, JDK 1.6 and Eclipse 3.7.0
00:25	For this tutorial, you should have knowledge of arrays in Java.
00:30	If not, for relevant tutorials, please visit our website which is as shown. [1]
00:35	The methods for array operations are available in a class called Arrays.
00:40	To access them, we need to import that class.
00:43	It is done by the statement import java.util.Arrays semicolon.
00:50	We can access a method from the class.
00:52	We do it by adding a 'dot' and the method name.
00:56	So, Arrays dot toString means toString method from the Arrays class.
01:05	Now switch to eclipse.
01:08	We have already created a class ArraysDemo.
01:13	Let us now import the class Arrays.
01:16	The import statement is written before the class definition.
01:22	So, before public class, type:
01:26	import java.util.Arrays semicolon
01:46	This statement says that java contains a package called util which contains the class Arrays and it has to be imported.
01:59	Now, let us add an array.
02:01	Inside the main function, type:
02:03	int marks open and close square brackets equal to within curly brackets 2, 7, 5, 4, 8
02:20	Now we shall use a method available in the Arrays class to get a string representation of the array and print it.
02:28	So, type: String mStr equal to Arrays dot toString parentheses inside parentheses will give the array name i.e. marks.
02:50	Now, this toString method will give the string representation of the array.
02:56	We shall print the marks.
02:58	So, type System dot out dot println inside parentheses type mStr;
03:12	Now, let us look at the output. So save and run the program.
03:18	As we can see in the output, the toString method has given a string representation of the array.
03:26	Now, let us look at sorting the elements of the array.
03:31	So, before the line Arrays dot toString type: Arrays dot sort within parentheses the Array name i.e marks.
03:46	So, the sort method in the Arrays class sorts the elements of the array passed to it.
03:53	Now we are sorting the elements of the array marks and then printing the string form of it.
04:04	Let us look at the output. So save and run.
04:11	As we can see in the output, the sort method has sorted the array in the ascending order.
04:19	Note that the sort method has changed the array itself.
04:22	This type of sorting is called inplace sorting.
04:26	It means that the array which contains the elements is changed as a result of sorting.
04:33	The next method we are going to look at is fill.
04:38	The fill method takes two arguments.
04:43	Remove the sorting line and
04:50	type: Arrays dot fill within brackets the name of the array i.e marks;
05:05	This is our first argument and second is the value that should be filled in the array, we will give it 6 and semicolon. Save and Run.
05:24	As we can see, as the name goes, the fill method fills the array with the given argument i.e 6.
05:32	The next method we are going to look at is copyOf.
05:37	We are going to copy all the elements of the array marks into the array marksCopy.
05:44	So, remove 'arrays dot fill'.
05:48	And type: int marksCopy[];
05:59	Next line, type: marksCopy = Arrays.copyOf(marks, 5);
06:25	This method takes two arguments.
06:29	The first argument is the name of the array from which you want to copy the elements.i.e marks.
06:39	The second is the no.of elements to copy, over here we will copy 5.
06:47	Then, in arrays dot toString, change marks to marksCopy.
06:55	Now save and run the program.
07:01	We see that the elements of the array marks have been copied to the array marksCopy.
07:10	Let us see what happens if we change the no.of elements to be copied.
07:15	Let's Change 5 to 3.
07:19	Save and Run.
07:24	As we can see, only the first three elements have been copied.
07:31	Let us see what happens if the no.of elements to be copied is greater than the total no.of elements in the array.
07:39	So, change 3 to 8.
07:44	Save and Run the program.
07:48	As we can see, the extra elements have been set to the default value which is 0.
07:54	Next, we'll see how to copy a range of values.
07:58	So, change copyOf to copyOfRange and 8 to 1, 4.
08:15	This method copies all the elements starting from the index 1 and stopping at index 3.
08:27	Save and Run.
08:31	As we can see, the elements from index 1 to 3 have been copied.
08:39	Note that we have given 1, 4 as our arguments.
08:47	But, even then the element at index 4 has not been copied.
08:50	Only the elements till index 3 have been copied. It stops one index before the given range.
09:01	So, this behavior ensures that continuity of ranges is maintained.
09:07	(0, 4) implies from index 0 to 3.
09:12	(4, 6) will imply index from 4 to 5.
09:17	So it behaves as if (0, 4) + (4, 6) = (0, 5).
09:26	This brings us to the end of this tutorial.
09:31	In this tutorial, we have learnt:
09:33	How to import the class Arrays.
09:36	Perform array operations like toStrings, sort, copy, fill.
09:44	For assignment:
09:46	Read about the Arrays.equals method and find out what it does.
09:53	To know more about the Spoken Tutorial project,
09:55	watch the video available at [2].
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10:22	Spoken Tutorial project is a part of the Talk to a Teacher project and is supported by the National Mission on Education through ICT, MHRD, Government of India.
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10:39	This tutorial has been contributed by TalentSprint. Thanks for joining.
10:43	This is Prathmesh Salunke, signing off. Jai Hind.

Contributors and Content Editors

Gaurav, Krupali, PoojaMoolya, Sandhya.np14, Sneha