Initialising 2D object

[porrum doctum]

Hi,

I have been experimenting with a class creating 2D objects and defining functions using them. You could interpret it as a classic matrix class I suppose.

There's the method of using:

template <typename T>
T ** object2D;
object2D = new T*[rows];
for(int i=0;i<rows;i++)
{
   object2D[i] = new T[cols];
}

Tried that, it works. Currently I'm using a vector approach:

template <typename T>
vector<vector<T>> object2D;

In both cases, elements can be accessed through the simple object2D[i][j]. That way I can read the whole object and edit it elementwise.

I am however looking for a way to initialise the whole thing at once instead of having to do it element by element.

Something like this possibility if you define a new array: double x[2][2] = {{1,2},{3,4}};

I want to be able to do that with my own object, perhaps through operator overloading? Any suggestions would be most welcome. Also, I assume this is newbie enough for the beginners forum, but if it isn't please alert me and do not just leave me without an answer. Thanks in advance.

[Zaita]

http://www.cplusplus.com/forum/articles/7459/

Initialising multi-variable arrays (esp as a vector) is very difficult. You have to remember, what if someone overrides your template with a class?

[seymore15074]

Note that a vector containing a vector must be declared without using two >'s next to each other. >> would be parsed as a single token.

[porrum doctum]

Zaita, I understand that this definition is not foolproof, but that is not something I'm currently looking to change. It works for what I am using it for and that's for the moment fine by me. I had already read what you linked. Thanks though, it certainly is an interesting post.

I still don't know however, whether there is a method that would allow me to initialise multiple elements at once, with a function or an operator overload. Anyone?

And Seymore, I see how that could be a problem, but I didn't encounter any troubles. I'll remember it for if I ever do get an error relating to that.

[jsmith]

FWIW, boost::array allows you to use array syntax to assign elements:

boost::array<6> array = { 1, 2, 3, 4, 5, 6 };

Newer compilers handle the >> ambiguity.