access violation in deleting a 2d array

Question

I have a 2d array of object pointers, and I am trying to write a deallocator for an object that to delete both the pointers in the array, and then delete the array itself. I define the array in the header of the object to be destructed like so

    space* board[6][6];

I allocate the space objects in the array like so:

    board[0][0]= new space(1,0);
    board[0][1] = new space(1, 0);
    board[0][2] = new space(1, 0);

My current destructor is like this

    for (int i = 0; i < 6; ++i)
{
    for (int j = 0; j < 6; ++j){
        delete board[i][j];
    }
    delete[] board[i];
}
delete[] board; 

When I do this, I get this message: Unhandled exception at 0x5080A9E8 (msvcr120d.dll) in Blitz.exe: 0xC0000005: Access violation reading location 0xFEEEFEE2.

I'm not quite sure what to do, I've tried looking around, and it seems like my destructor should be okay. I know if I had a decent programming education, I would use something better, like a vector or something else. I downloaded a pdf on how people actually use C++ these days, and I'll probably go over that soon, but I would just rather just take care of this memory leak and move on.

Answer 1

You are mixing new with delete[] . The behaviour of your program is therefore undefined .

It would be marginally better if you used std::vector<std::vector<space>> instead. Then, the memory management would be done for you.

But if you're modelling a matrix then this is also not a good choice: it will have a "jagged edge" and the memory allocated is not contiguous.

A good alternative would be to allocate a contiguous block and use the convention (i * rows + j) for the element at (i, j) . A std::vector<space> would suffice. Then consider using a 3rd party matrix library like BLAS (www.boost.org).

Answer 2

board和board[i]变量不应delete d，因为它们尚未由new分配。