Why core dump??

I cant figure out why I continue to get a core dump with this function. I'm trying to print out the numbers 3, 5, 7, 9, 11, 13

_num, field_size, and num_per_line are all equal to 6 when I call the function

Code:

---

void Vect::tellsome( ostream & out, int field_size, int num_per_line)
{
  for(int i = 0; i < _num; ++i)
  {
    if((i % num_per_line) == 0)
    {
      out << endl;
    }
    out << setw(field_size) << _data[i];
  }
}

---

> I cant figure out why I continue to get a core dump with this function
Probably because the problem is really somewhere else, and here is just where you get to notice that there is a problem.
We really need the whole program (or a complete sub-program which also crashes) to comment in any meaningful way.

Except to say that you need to check every pointer, and every new call in your code.