Difference between revisions of "Java/C2/Introduction-to-Array/English-timed"

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|  In this tutorial, you will learn how  to create '''arrays''' and  access elements in '''array'''s.
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|  In this tutorial, you will learn how  to create '''array'''s and  access elements in '''array'''s.
  
 
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* '''Ubuntu 11.10'''
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* '''JDK 1.6''' and  
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| '''int rainfall''' open  and close   brackets equal to within curly brackets type '''25, 31, 29, 13, 27, 35, 12''' and finally a semicolon.  
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  | This is because when we create an '''array''' of integers, all the values are initialized to 0.  
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|  | As we can see, we are printing the  value of sixth element in  '''array'''. So, '''Save''' and '''run'''.  
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|  The Spoken Tutorial project team: Conducts workshops using spoken tutorials and gives certificates for those who pass an online test.  
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|  The Spoken Tutorial project team: Conducts workshops using spoken tutorials and gives certificates to those who pass an online test.  
 
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Latest revision as of 19:29, 20 February 2017

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.
09:10 To know more about the Spoken Tutorial project,
09:13 watch the video available at the following link.
09:19 It summarizes the project. If you do not have good bandwidth, you can download and watch it.
09:26 The Spoken Tutorial project team: Conducts workshops using spoken tutorials and gives certificates to those who pass an online test.
09:34 For more details, please write to contact AT spoken HYPHEN tutorial DOT org.
09:40 Spoken Tutorial project is a part of the Talk to a Teacher project.
09:44 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
09:50 More information on this mission is available at spoken HYPHEN tutorial DOT org SLASH NMEICT HYPHEN Intro.
09:57 This script has been contributed by TalentSprint.

This is Prathamesh Salunke, signing off. Thanks for joining.

Contributors and Content Editors

Jyotisolanki, PoojaMoolya, Sandhya.np14, Sneha

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