How do I declare a 2d array in C using new

Question

How do I declare a two-dimensional array using new?

For example, for a "typical" array, I would:     

int* ary = new int[Size]

but

int** ary = new int[sizeY][sizeX]

a) doesn't work/compile and b) doesn't accomplish what:

int ary[sizeY][sizeX] 

does

Answer 1

int** ary = new int[sizeY][sizeX]

should be:

int **ary = new int*[sizeY];
for(int i = 0; i < sizeY; ++i) {
    ary[i] = new int[sizeX];
}

and then clean up would be:

for(int i = 0; i < sizeY; ++i) {
    delete [] ary[i];
}
delete [] ary;

A different way would be to employ a single huge block of memory:

int *ary = new int[sizeX*sizeY];

// ary[i][j] is then rewritten as
ary[i*sizeY+j]