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Index › Programming Questions & Help › Syntax Questions › How to write an array contains another array
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How to write an array contains another array? (Read 940 times)
shrieker
How to write an array contains another array?
Sep 18th, 2009, 5:26am  
Hi~
I want to judge whether a pattern which comprising 4 points is symmetrical.
What I think is translate 4 points as below:
 //(x, y)  -> (y, -x) 90 degrees
 //(x, y) -> (-x, -y) 180 degrees
 //(x, y) -> (-y, x) 270 degrees
 //(x, y) -> (x, -y) x axis
 //(x, y) -> (-x, y) y axis
 //(x, y) -> (-y, -x) diagonal\
 //(x, y) -> (-y, x) diagonal/
then, I get a new set of points:
{(x1,y1),(x2,y2),(x3,y3),(x4,y4)} -> {(x1',y1'),(x2',y2'),(x3',y3'),(x4',y4')}
After that I can compare this 2 sets of points, to see whether they coincide.

But I don't know how the syntax could be. Is it possible to write an array with 4 elements that contains another array with 2 elements?
Or is there a better way to figure out whether the pattern is symmetrical?
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bartk
Re: How to write an array contains another array?
Reply #1 - Sep 18th, 2009, 5:48am  
Not quite sure what you mean by "symmetrical" points. Could you give at least one example of a symmetrical set of points and also at least one example of a set of points that is not symmetrical?
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PhiLho 
Re: How to write an array contains another array?
Reply #2 - Sep 18th, 2009, 6:09am  
For the first question at least, the answer is simple:
Code:
int[][] points = { { 1, 2}, {3, 4}, {5, 6}, {7, 8} };
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shrieker
Re: How to write an array contains another array?
Reply #3 - Sep 18th, 2009, 6:18am  
Sorry to forget mentioning that all the points is in a coordinate system with boundary.
Suppose there're 4 points{ (-2,2) (2,2) (-2,-2) (2,-2)}, which composed a square that is symmetrical.
but if the 4 points are {(-2,1) (1,1) ((2,-1) (1,-2)}, then it's not symmetrical.
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shrieker
Re: How to write an array contains another array?
Reply #4 - Sep 18th, 2009, 6:23am  
PhiLho  wrote on Sep 18th, 2009, 6:09am:
For the first question at least, the answer is simple:
Code:
int[][] points = { { 1, 2}, {3, 4}, {5, 6}, {7, 8} };


I want to write something like this:

int [] apoint = new int[2]
int [] [] points= new int [4] [ apoint[] ]

I know it's probably not correct, but I hope it make what I want clearer.
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PhiLho 
Re: How to write an array contains another array?
Reply #5 - Sep 18th, 2009, 7:19am  
Code:
int[][] points = new int[4][2];
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