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| − | I'm new to java, and my lack of understanding Java has me hung up on this key peice of code:
| + | If you were looking for the discussion between Martin and Justin, it's on the [[Talk:GFTargetingBot|talk page]]. |
| − | buffer = statBuffers[distanceIndex][velocityIndex][lastVelocityIndex];
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| − | from my understanding; buffer is an array of 25 (ints), each bin being a counter of times visted.
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| − | And statBuffers is a 4dimesional array of size: 5(int), 5(int), 5(int),and 25(int) :
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| − | private static int[][][][] statBuffers = new int[DISTANCE_INDEXES][VELOCITY_INDEXES][VELOCITY_INDEXES][BINS];
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| − | so back to the problem code :
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| − | buffer = statBuffers[distanceIndex][velocityIndex][lastVelocityIndex];
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| − | so the above "indexes" (0-4) should retrieve the values in thoses locations in the statBuffers arrays..
| + | ---- |
| − | Am I wrong so Far ?
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| − | It seems to me were assigning apples to oranges here? How does it work ? ..
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| − | - Justin | |
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| − | <code>int single[] = new int[ 5 ];</code>
| + | Article migration from old wiki required. |
| − | <br><i>single</i> is "an array of integers".
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| − | <br><code>int double[][] = new int[ 5 ][ 5 ];</code>
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| − | <br><i>double</i> is "an array of 5 arrays of 5 integers".
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| − | This means that each element in double[ n ] is itself "an array of 5 integers".
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| − | <br>Let's change <i>int</i> to <i>apple</i>.
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| − | <br><code>apple double[][] = new apple[ 5 ][ 5 ];</code>
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| − | <br><i>double</i> is now "an array of 5 arrays of 5 apples."
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| − | This means that every double[ n ] is a container, and each container holds 5 apples. The container is not an apple. It is 'a container of one or more apples'. You can visualize it as a paper bag if you like.
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| − | <br><code>apple triple[][][] = new apple[ 5 ][ 5 ][ 5 ];</code>
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| − | <br><i>triple</i> is "an array of 5 arrays of 5 arrays of apples" or perhaps "5 containers of 'containers of apples'".
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| − | Going back to your original question, here is the situation: <i>buffer</I> is 'an array of integers'. (I deliberately did not state the size, because <i>buffer</i> can be assigned an array of any size of the same dimensions.) <i>statBuffers</i> is 'an array of arrays of arrays of arrays of integers'. Each element in statBuffers[][][] is itself an 'array of integers', and that is why the assignment works.
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| − | I hope that helped. If not, best thing is to just practice with arrays it until it sinks in. -- [[User:Pedersen|Martin]]
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| − | <i>Addendum:</i> Above you mentioned "statBuffers is a 4dimesional array of size: 5(int), 5(int), 5(int),and 25(int)", and therein lies the misconception. The "5(int)" sections are not arrays of integers. They are "arrays of arrays". The integers only exist in the final array. -- [[User:Pedersen|Martin]]
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| − | yes I wasn't thinking dimesionally :), in the case of GFTargengBot code: buffer ends up being the 4 dimension of statBuffer that corisponds to the first 3 dimensions..correct?
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| − | -justin
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| − | Correct. Also, <i>buffer</i> doesn't get its own copy of the data. It just refers to the same memory location for the data that that branch of statBuffer does. I doubt that's really relevant, but it may become relevant in some other application, and just saying "Correct." alone seemed silly. -- Martin
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| − | thx Martin :) -justin
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