plz help me out(Dynamic Allocation)

[nayannovellus]

how to create double dimensional and 3 dimensional arrays dynamically(using new operator).please help me out as soon as possible.

[Banfa]

I wouldn't try.

I would create a single dimensioned array and use arithmatic to calculate the correct index values.

For instance suppose you want the equivilent of

int array[X][Y][Z];

Where X, Y and Z represent any (sensible) integer value.

This actually has X*Y*Z entries so I would allocate a single dimensioned array with this many entries

int *array = new int[X*Y*Z];

and write a function to calculate the array index give x, y and z

inline unsigned arrayIX(unsigned x, unsigned y, unsigned z)
{
    assert(x<X);
    assert(y<Y);
    assert(z<Z);
 
    return (x*Y*Z+y*Z+z);
}
 

The I can use the function to access array

array[arrayIX(1,4,6)];

since arrayIX is inline and is doing a similar calculation to the one that would have to be done anyway there is not going to be a big difference in performance (especially for an optomising compiler)

and the new/delete process is much easier since it only envolves 1 new and 1 delete.