Pointer arithmetic with 2D vector
<p>I'm trying to understand pointer arithmetic in 2D vector.</p>

<p>I thought that if I have 2D vector at the size: <code>M[3][3]</code> and <code>*ptr=&amp;M[0][0]</code>
than <code>ptr[4]</code> is equal to <code>M[1][2]</code>, but it seems to be wrong.</p>

<p>Can you please help me out with this?</p>
