Please help! -- C-style 2D array containing std::vector

[a_sonhye]

I know it's weird but I would like to create a 2D c-style array. Each array element stores a vector of int. The result will produce 3D array of int.

I can compile my code but it seems like whenever I add some data into the vector and, later I want to display it, there is no data in the vector!!!

Please let me know what I did wrong. Thank you very much.

typedef std::vector<int> VEC_INT;

// Create array of vector
VEC_INT ** ppSubRegion;
VEC_INT * pSubRegion;
ppSubRegion = (VEC_INT **) malloc(SUBPATTERN * sizeof(VEC_INT *));
pSubRegion = (VEC_INT *) malloc(SUBPATTERN * SUBPATTERN * sizeof(VEC_INT));

for (int i = 0; i < SUBPATTERN; i++)
{
ppSubRegion[i] = &pSubRegion[i*SUBPATTERN];
}

// Add numbers into the vector according to some criteria. There is no error!
((VEC_INT) ppSubRegion[nRow][nCol]).push_back(iNumber);

// After display, it shows that the vector contains nothing.
(VEC_INT)(ppSubRegion[r][c]).size() <----- return 0!

Thank you very much