Java/C2/Introduction-to-Array/English-timed

Time	Narration
00:02	Welcome to the spoken tutorial on Introduction to Arrays.
00:07	In this tutorial, you will learn how to create arrays and access elements in arrays.
00:14	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 data types and for loop in Java.
00:32	If not, for relevant tutorials, please visit our website which is as shown.
00:38	Arrays are a collection of data.
00:40	For example, a list of marks, a list of names, a list of temperatures, a list of rainfall.
00:47	Each item has an index, based on its position.
00:52	The index of the first element is 0.
00:55	The index of the second element is 1 and so on.
00:59	Let us now see how to store this data.
01:03	So switch to Eclipse.
01:06	A class named ArraysDemo has already been created.
01:11	Within the main method, let us add the rainfall data.
01:16	So, inside main function, type:
01:18	int rainfall open and close square brackets equal to within curly brackets type 25, 31, 29, 13, 27, 35, 12 and finally the semicolon.
01:53	Note that the square braces after the variable name rainfall.
01:58	This declares rainfall as an array of integers.
02:03	The braces are used to specify the elements of the array.
02:09	Let us now access data.
02:12	So on the next line, type:
02:14	System dot out dot println rainfall in square brackets type 2.
02:28	We are printing the element with the index number 2.
02:32	In other words, the third element in the array i.e. 29.
02:38	Let us save and run the program.
02:43	As we can see, the output is the third element, i.e 29.
02:49	Now, let us type 0 in place of 2.
02:56	Save and run the program.
03:00	As we can see, the output is the first value i.e 25.
03:07	Now, let us modify the value of the first item.
03:13	So, type: rainfall[0] = 11;
03:27	Now, let us see its value. So save and run the program.
03:34	As we can see, the value has been changed to 11.
03:40	Now, what if we know only the size of the array and do not know the values.
03:45	Let us see how to create such array.
03:49	Remove everything in main function and type:
03:57	int squares[] = new int[10];
04:19	This statement creates an array of integers having 10 elements. The name of the array is squares.
04:30	Now, let us add some values to it.
04:33	So, type:
04:35	squares[0] = 1;
04:43	Next line, squares[1] = 4;
04:53	Next line, squares[2] = 9;
05:04	squares[3] = 16;
05:15	So, we have entered the squares of first four numbers.
05:20	Now what about the other elements of the array. Let us see what they contain.
05:26	So, we shall print the sixth value in the array.
05:30	Type: System S capital .out.println(squares[5]);
05:56	Save and run the program. We see that the value is zero.
06:05	This is because when we create an array of integers, all the values are initialized to 0.
06:11	Similarly, an array of floats will have all its values initialized to 0.0.
06:18	It would be a long process if we have to type each value into the array. Instead, let us use a for loop.
06:28	So, type: int n, x ; for(x = 4; x < 10; x = x + 1){ n = x + 1; squares[x] = n * n; }
07:25	So, we iterate over numbers from 4 to 9 and set the corresponding element in the array.
07:36	Now, let us see the output.
07:38	As we can see, we are printing the value of sixth element in array. So, Save and run.
07:52	We see the sixth element is now square of 6 which is 36.
07:57	In fact, now we can set all the values inside the for loop.
08:03	Remove the lines that set the values manually and change 4 to 0.
08:14	This way, all the elements from index 0 to 9 are set to the corresponding squares.
08:21	We shall now see the value of the third element.
08:25	So, change 5 to 2.
08:30	Save and run.
08:35	As we can see, the value of the third element has been set in the loop and it is 9.
08:42	This way, arrays can be created and used.
08:50	We have come to the end of this tutorial.
08:53	In this tutorial, we have learnt:
08:55	* To declare and initialize an array.
08:58	* And access an element in an array.
09:01	The assignment for this tutorial is:
09:04	Given an array of integers, find the sum of all the elements in the array.
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Jyotisolanki, PoojaMoolya, Sandhya.np14, Sneha