ID:183481
 
Multidimensional arrays are not limited to two indices (i.e., two dimensions). They can contain as many indices as needed. But be careful! The amount of memory needed for an array rapidly increases with each dimension. For example:

char century [100][365][24][60][60];


declares an array with a char element for each second in a century, that is more than 3 billion chars. So this declaration would consume more than 3 gigabytes of memory!

COOL! Just thought I'd share it with you. :D

http://www.cplusplus.com/doc/tutorial/arrays.html
CaptFalcon33035 wrote:
Multidimensional arrays are not limited to two indices (i.e., two dimensions). They can contain as many indices as needed. But be careful! The amount of memory needed for an array rapidly increases with each dimension. For example:

Right, the amount of memory can be computed by multiplying each 'dimension', and then multiplying by the number of bytes required for the data-type. In this example, you used a char---a typical one-byte type.

> char century [100][365][24][60][60];
>

declares an array with a char element for each second in a century, that is more than 3 billion chars. So this declaration would consume more than 3 gigabytes of memory!

Well, not quite 3 gigabytes. Nearly 2.94 GB by my calculations*. Still, that is a bit atrocious, and the problem is even more devastating when not using the simple char type; imagine if you used a simple 4-byte int, or a class/struct consisting of as many as 10 bytes.

<small>*
Number of bytes: 100*365 = 36500, * 24 = 876000, * (60*60 = 3600) = 3153600000.
Number of bytes in a gigabyte = 1024 (KB) * 1024 (MB) * 1024 (GB) = 1024^3 = 1073741824.
Number of gigabytes in array: 3153600000 / 1073741824 = 2.937 (a bit nitpicky, eh? :P)</small>

Anyways, what's more interesting is how changing just one of those values impacts the size overall. As an example:
char century[101][365][24][60][60];

Which results in an increase of 31536000 bytes (365 * 24 * 3600), or roughly 30 MB.

Hiead
Ok... now fill it with Lorem Ipsum

`Kujila
You can do that with BYOND lists too.

var/list/L = list("one"=list("one"=list("one"="Wee")))

Then you just grab the data like so:

L["one"]["one"]["one"] = "Wee"
In response to Nadrew (#3)
Doesn't the limit crash the world for having too many lists when you reach a list that large?
In response to CaptFalcon33035 (#4)
Only if you have 65536 or more of them. Each list within a list only counts as one towards the limit.
CaptFalcon33035 wrote:
Multidimensional arrays are not limited to two indices (i.e., two dimensions). They can contain as many indices as needed. But be careful! The amount of memory needed for an array rapidly increases with each dimension. For example:

> char century [100][365][24][60][60];
>


declares an array with a char element for each second in a century, that is more than 3 billion chars. So this declaration would consume more than 3 gigabytes of memory!

COOL! Just thought I'd share it with you. :D

http://www.cplusplus.com/doc/tutorial/arrays.html

I can understand three or four dimensions...but five?
In response to Shlaklava (#6)
Shlaklava wrote:
I can understand three or four dimensions...but five?

Apparently you weren't around for that October Contest a while back. :)

Hiead
In response to Hiead (#7)
Yeah, didn't you get the memo?