System.out.println ();

[Twixmaster123]

This isn't necessarily a build issue I just have a question about

int[] data = {3, 2, 4, 3, 1, 0};
data[1] = data[1] + data[3];
System.out.println ( data[1] );

...the test said the output is 5, but how can there be a output if data[1] and data[3] haven't been established yet?

[wsaryada]

What do you mean by the data haven't been established? In the first line you clearly declare and initialize the data array. In the second line you assign a new value for data[1] by adding the original value of data[1] and data[3] which mean 2 + 3. And this is of course give you 5 as the output.

[Twixmaster123]

I understand in the second line I am assigning a new value for data[1] but I am not understanding what the original value of data[1] and data[3] is. How is it 3 and 2? Wouldn't be 3 and 4? I guess I am just lost on where your getting the original values of data[1] and data[3]. Clarification on how its 2 and 3 would be great! Thanks for the quick reply.

[wsaryada]

The index of an array started from 0 not 1. This mean when you access data[1] it will give you 2, when you access data[0] it will give you 3.

[Twixmaster123]

data[1] = 2 (how?) and data[0] = 3? So its saying data[3] hasn't been established yet and equals 0 or 3. Which gives us 2+3 then outputs 5, I get that much. Still lost on how data[1] = 2 and how data[3] is just 3? ^_____^

[pbrockway2]

int[] data = {3, 2, 4, 3, 1, 0};

Just wondering, but what do you think this line does?

[wsaryada]

Please read the following tutorial for you to understand the basic of an array. Arrays (The Java™ Tutorials > Learning the Java Language > Language Basics)

[Twixmaster123]

To answer your question pbrockway2: Its initializing the data array with the numbers 3, 2 , 4, 3, 1, 0?

[wsaryada]

Ok, you understand that it initialize your array. Now if you want to access the first value of your array which in this case is 3 how do you do it? What is the index of the first element of your array, or if I say it as data[x] , what is x?

[Twixmaster123]

data[1] = 3 and data[3] = 2?

[wsaryada]

When you have:

int[] data = {3, 2, 4, 3, 1, 0};

The corresponding index and value of the array will be:

data[0] = 3;
data[1] = 2;
data[2] = 4;
data[3] = 3;
data[4] = 1;
data[5] = 0;

The index of an array started from 0 (zero). I hope this can make it clear for you.

[Twixmaster123]

DURP! I think I just had the light bulb....the index of the array starts like 0,1,2,3,4,5 and the data is 3,2,4,3,1,0. So since the first value of the array is 3,

data[0] = 3;
data[1] = 2;
data[2] = 4;
data[3] = 3;
data[4] = 1;
data[5] = 0;

and so on...

data[1] = data[1] + data[3];

So here were taking data[1] which in this case is 2 and data[3] which in this case is 3 and doing simple addition and then outputting 5 to a new line, correct?

[pbrockway2]

data[1] = 3 and data[3] = 2?

I have no idea where you got the values 3 and 2 from.

You are quite right - that line is initialising the array. In other words: it is putting values into the array. This more or less answers your question "Still lost on how data[1] = 2 and how data[3] is just 3?". They have those values because the array was initialised to have them.

Again your supposition that "data[1] and data[3] haven't been established yet" turns out to be wrong. data[1] and data[3] have been *established* (in the sense of "initialised") precisely by that line of code.

wsaryada's post (#11) shows exactly how the initialisation sets (/establishes/initialises) each of the elements of the data array.

[Edit] ... slow ;(

[Twixmaster123]

Yeah I corrected myself in the post above your last :P. Thanks guys for walking me through my episode of stupidity!