matrix multiplying

I have seen all the other threads but I can't get mine to work. I am trying to multiply two matrices with overloading operators.

mat[SIZE][SIZE] is my private variable
SIZE is initalized to 2 for now

Code:

Matrix & Matrix::operator *= ( const Matrix & rhs )
{
  Matrix temp;
  for(int i = 0; r < SIZE; ++i)
  {
    for(int j = 0; j < SIZE; ++j)
    {
      for(int k = 0; k < SIZE; ++k)
      {
        mat[i][j] += mat[i][k] * rhs.mat[k][j];
      }
    }
  }
  return * this;
}


Matrix Matrix::operator *  ( const Matrix & rhs ) const
{
  Matrix ret_val (* this);
  ret_val *= rhs;
  return ret_val;
}

I believe you had it right the first time. I'm pretty sure you need a temporary to do the multiplication. But then once temp holds the result, you must then copy temp to mat before returning *this.

You're the man. Thanks!!