data containers

[Moritz]

Thanks again, torhu. I understand multidimensional arrays (at least I 
think so :-) ), and that these arrays contain pointers to other arrays.

I thought the .length() operation would make the array static in its 
size, thats why I didnt try this earlier.

But after reading what you wrote, I still dont see why I cant go without 
the length(), by just using ~=, like:

ScreenElement[][]	layer_map;

int add_element(ScreenElement new_element, uint layer)
{
	layer_map[layer] ~= new_element;
}

You wrote setting the length and using ~= both increase the size of the 
array, but I get an ArrayBoundsError when using the ~=.

And thank you all for your help so far!!!!

torhu schrieb:
> Moritz wrote:
>> Thank you torhu, I finally managed to get something into this array! :-)
>>
>> But I still dont understand if and how I can add a new ScreenElement 
>> array to the layer map *without* setting its size in advance(because I 
>> want to remain as generic as possible).
> 
> I'm wondering if you're aware what a two-dimensional array really is.
> 
> When you do this:
> 
> ScreenElement[][] layer_map = new ScreenElement[][5];
> 
> layer_map.length will be 5.  But the lengths of the arrays in the second 
> dimension will all be zero.  For example, layer_map[0].length and 
> layer_map[3].length will be zero.  So you have allocated space for 5 
> arrays of ScreenElements, but no space for the ScreenElements 
> themselves.  Just 5 array references that don't have any space to refer 
> to yet.
> 
> I hope this makes sense to you.
> 
>>
>> And another question: Can I modify the size of an array after I set it 
>> manually?
> 
> Sure, these two will work anytime:
> 
> array.length = whatever; // set length to whatever
> 
> array ~= stuff;  // increase length by 1, add 'stuff' at end
>