#### Archived

This topic is now archived and is closed to further replies.

# Stupid question about 2-Dimensional Arrays

This topic is 5788 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

Okay I feel like an idiot for asking this, but it''s been 4 years since i''ve done anything with a 2 dimensional array. So here we go: I want a grid that is 7 across and 5 down, how would I make that into a 2D array? int array[7][5] or int array[5][7]? I''m confused :/ Sorry for the stupid question. -Laz

##### Share on other sites
*shrugs*

It''s all data ^_^

If you access your array using ''list[x][y]'', then ''int list[7][5]''.

If you access your array using ''list[y][x]'', then ''int list[5][7]''.

##### Share on other sites
It doesnt make the slightest difference, what makes it 7 across by 5 down is how you process it.

Personally I''d do it as [7][5] (width, height).

NightWraith

##### Share on other sites
It really don''t matter as long as you stick to your own definition of which is which.

n-dimensionals are slow (2dim is about 3 times slower than a 1dim used as a 2dim...did a small test-app in cs class once..).

##### Share on other sites
Well I just thought about it and I can eliminate the confusion and probably free up some memory by using a linear array. It''s a custom data type and in my structure I have xPos and yPos, so I can just go through the linear array displaying each element at it''s xPos and yPos ... I guess I was thinking of 2D arrays because it will help visualize how the grid is supposed to look... if that makes sense...

##### Share on other sites
Its basically arbitrary. As long as you stay consistant, either way works. The only thing I''d observe is how many pointers you''d have. 7*5 = 35 cells. However, C arranges multidimensional arrays as arrays of pointers to other arrays. So, you''d have 5 pointers if it was array[5][7] and 7 pointers if it was array[7][5]. So, you in fact have 40 and 42 memory cells in use in each situation respectively. Though, with computers today pushing the limits of a 32bit address space, I don''t think you should worry about it. In fact, if you haven''t learn pointers, or, just aren''t comfortable with them yet, ignore my post.

-> Will Bubel
-> Machine wash cold, tumble dry.

##### Share on other sites
Pointers kinda confuse me, but i''m workin on learning them.

##### Share on other sites
It does make some slight difference, at least with pointer calls:

  int a[5][6];int *p_a = &a[2][3];*(p_a + 1) = 5; //a[3][3] or a[2][4]???

I''m not totally sure about this, but I think it would be a[ 2 ][ 4 ]... I''d have to check, though.

Cédric

1. 1
2. 2
3. 3
4. 4
Rutin
18
5. 5

• 11
• 22
• 12
• 12
• 11
• ### Forum Statistics

• Total Topics
631406
• Total Posts
2999904
×