Warp wrote:
> Orchid XP v8 <voi### [at] devnull> wrote:
>> Oh, er... can you have a vector of vectors? Or would it have to be a 
>> vector of vector pointers?
> 
>   It's perfectly possible.

OK. I just wasn't sure if it's permissible for the element type to be of 
variable size, that's all.

>   When you start having nested data containers, it may be useful to abstract
> a bit.

Agreed.

>   Of course there's no limit on how many containers you can nest.
>   Managing all this in your head might become a bit complicated, though. :)

Hence the abstraction. ;-)

Presumably I'm going to do something like define a struct that holds all 
the data I need about each symbol (what the symbol is, its probability, 
its current codeword, etc), and then define a typedef for a vector of 
symbol info structs. Then it'll be quite clear that vector<tree> is a 
vector of Huffman trees.

>   For example, if you want a vector of huffman trees, it would be a bad
> idea to try to manage them directly. Instead, it's a much better idea to
> abstract the whole huffman tree concept, and then use that as the element
> of the outermost vector. In other words, something like:
> 
> class HuffmanTree
> {
>  public:
>     // A nice and easy-to-use interface here
> 
>  private:
>     typedef std::vector<int> IntCont;
>     std::vector<IntCont> theTree; // Or whatever
> 
>     // Other possible private members
> };
> 
>   Now you can do this:
> 
> std::vector<HuffmanTree> trees; // A vector of huffman trees
> 
>   So here you have three levels of nesting of vectors, but they are so
> well abstracted that it's easily manageable. In the outermost layer you
> only see the HuffmanTree class and its simple public interface.

...or I could do that, yes. That would provide an obvious place to put 
the "tree merge" functionallity, as well as symbol lookup, etc.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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