pointer & array question

My first impression of your code was that you wanted to iterate over an array of type My_dynamic_2d_array. After a closer look, I see you want to iterate over the array within the object. This means you need to provide a getData() template function to get the array pointer within the object, then use that to iterate over.

Ignoring the fact that you got your pointers mixed up (the pointer to object My_dynamic_2d_array, is not the same as the pointer to My_dynamic_2d_array->m_data), the reason your compiler doesn't like the line of code, is that it tells the compiler that you want to assign the address My_dynamic_2d_array to an int pointer. While the fact that you're assigning a pointer to a pointer seems fine on the surface, the compiler doesn't like this for cases just like the sort of thing you do in your code:

pSrc++;

That line tells the compiler to increment the pointer the same number of bytes as is allocated for the pointer's data type, in this case "int", which is typically 4-bytes on most systems. Your class is 2 int's and a pointer...at least 12-bytes on a typical system (maybe with some added overhead as well). See the problem?

You [I]can[/] try overriding the pointer operator, but that'll probably get you into trouble if you want to work with the actual pointers to the objects, rather than the pointers to the enclosed data array. So, unless you can think of a really clever way to pull it off, stick with the approach below:

*T getData() const
{
return m_data;
}

OK, maybe I was too inspecific...

getData() should be a public function in your template class, which means you should be able to do something like
My_dynamic_2d_array.getData()
to get the underlying array.

Oh, and that should be T* not *T... my bad. It's probably OK to make it inline, too.

Last point, you're iterating through the array in main(), but you're not using your index operator you defined...any reason?

Here's a modified version of the main() function using the correct syntax and access methods for this class.

int m_size, m_width =3, m_Height=4;
int main()
{
m_size = m_width * m_Height;
dynamic_2d_array < int > My_dynamic_2d_array(m_width, m_Height);
int *pSrc = &My_dynamic_2d_array[0][0];
int testvalue = 0;
for (int x = 0;x<m_width;++x)
{
for(int y = 0;y<m_Height;++y)
{
My_dynamic_2d_array[x][y] = testvalue++;
}
}

cout << "Example using index ..." << endl;
int *pSrcEnd = &My_dynamic_2d_array[m_width-1][m_Height];
while(pSrc < pSrcEnd)
{
cout << *pSrc << ", ";
pSrc++;
}

pSrc = &My_dynamic_2d_array[0][0];
cout << endl << "Example using m_size ..." << endl;
pSrcEnd = (&My_dynamic_2d_array[0][0]) + m_size;
while(pSrc < pSrcEnd)
{
cout << *pSrc << ", ";
pSrc++;
}