If I'm using a 1d array to represent a square board, how can I take my index and check the sqaures a

Posted by FrankTheTank on Stack Overflow See other posts from Stack Overflow or by FrankTheTank
Published on 2010-04-18T21:02:37Z Indexed on 2010/04/18 21:13 UTC
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language-agnostic

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game

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modulus

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arrays

If I have a 4x4 gameboard which I'm representing in my program as a 1d integer array of size 16.

How can I get the indexs of the squares above, below, to the left and to the right any given index?

So, for example:

A = { 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 }

Which represents this board

 0   1   2   3
 4   5   6   7
 8   9  10  11
12  13  14  15

Lets say I am currently on index #8 in the board (value = 7). How can I get the index for 4 (value = 3) , 5 (value = 6), 10 (value = 11) and realize that there is no right square because it is on the right hand edge of the board.

I know I need to use some modulus math but I'm failing to come up with the right way to get the indexes for adjacent squares.

I'm thinking something like...

if ((i % 4) + 1 < 3) right = i + 1;
if ((i % 4) - 1 > 0) left = i - 1;
if ((i % 4) + 4 < 15) bottom = i + 4;
if ((i % 4) - 4 > 0 ) top = i - 4;

Does this seem like it is the right approach?

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