Spec interpretation

[Danwd]

I don't actually need any coding help, however, in my coursework to create a sudoku solver, I have to create something "defined as an array of nine CellGroup
objects, linking to a total of 81 Cell objects" for the row, column and 'block'.

I am not sure how to do this? Maybe something like linked list or something? I don't know.

[Peter87]

I think they mean linking in a more abstract sense, that you should be able to get to/access the 81 Cell objects somehow by using the array of 9 CellGroups. You don't want to use a linked list here. Arrays are all you need.

[Danwd]

Oh ok, so would I create an array containing 9 cells? or 81?

[TwilightSpectre]

I think they want an array of 9 'Cellgroup', and each 'Cellgroup' contains an array of 9 'Cell's.

[Peter87]

The description says you should have an array of 9 CellGroups. Exactly how you represent a CellGroup is up to you. It could simply be an array (an array with 9 elements or possibly a 3x3 2D array), or maybe a struct/class object containing such an array.

[Danwd]

Can you put arrays in arrays? Or am I just thinking this wrongly?

[Peter87]

sure.

int board[9][3][3];

Here board is an array of 9 int[3][3].

[AbstractionAnon]

How about something like this?

class Cell 
{  int            value;
    bool         fixed;
...
};
class CellGroup
{  Cell           cell[3][3];
...
};
class Board 
{  Cellgroup  cg[3][3];
...
};

[Danwd]

I've created an array of pointers in a cellgroup class,
Cell *cellPointers[9];
I created 3 more arrays for the row, column and block.

So my row array, has 9 arrays, each with 9 pointers in it. My question is, I need to populate the board with a text file, but how do I put all the 81 numbers into my row arrays, if you understand what I mean.

[AbstractionAnon]

I'm not sure why you need pointers to the cells. That creates memory mnagement issues and creates the potential for memory leaks. I think you will find it easier to treat the cellgroup as a 3x3 array of cells.

If you really want to use pointers, cellgroup's constructor will need to allocate 9 Cells and assign those pointers to the respective cellPointers.
Don't forget that cellgroup's destructor will need to delete those pointers.

[Danwd]

We have to use pointers for the coursework, and okay thanks, i'll see if i can do anything haha,

[Danwd]

Sorry for not understanding, but C++ confuses me.

I have 3 classes whcih are:

class Cellgroup
{

public:	
	Cell *cellPointers[9];
};

class Cell
{
public:
	std::vector<int> possibleCanidates;
	int value;
	bool cellFixed;

} board[9][9];

class Sudoku
{
public:
	Cellgroup row[9];
	Cellgroup column[9];
	Cellgroup block[3][3];
};

Am I suppose to be putting constructors anywhere? I guess I need to add some to the Cellgroup class, and probably the cell, but i'm not sure whatsoever.

[chipp]

an array(s) would be suffice, in my opinion :)

[Danwd]

hmm, i think i am going to use arrays, but i dont know my next step.

[AbstractionAnon]

Ahh, I see what you're doing with your Sudoku class. You have separate Cellgroups for the 9 rows, the 9 columns and the 9 blocks. I think that's making things more complicated. When you update a cell, you're going to have to update it in 3 places, actually 4 places if you include board[9][9]. I think it's much easier to keep one image of the state of the board, which is what I suggested in my earlier post.

Am I suppose to be putting constructors anywhere?

Yes, Cellgroup will need at a minimum constructor and destructor. You will probably also want a copy constructor and assignment operator. See:
http://en.wikipedia.org/wiki/Rule_of_three_(C%2B%2B_programming)
I explained the constructor in my earlier post.

And yes, Cell should have a constructor to initialize value and cellFixed. Do not assume that because you're always initializing from a file, you can do this at the time you read each cell from the file. If you create a temporary cell anywhere (such as pushing onto a vector) you're going to want it initialized.