Subj : Re: Returning structures from template classes
To   : borland.public.cpp.borlandcpp
From : maeder
Date : Sun Oct 02 2005 12:04 pm

"DJV" <ventruella@hotmail.com> writes:

[Too much prose and not enough C++ for may taste; I have great
difficulties understanding your problem. At least please illustrate
your prose with code or pseudo-code.]

> I am trying to return both a matrix and a simple unsigned integer
> from a matrix class in a header file to indicate whether a matrix
> has been successfully inverted.  It occurred to me to use a pointer
> to a structure, but two problems developed.

Why returning two things at the same time?

Is it because to determine whether a matrix is invertible requires you
to basically try to invert it? If this is the reason, consider
creating an inverter class. E.g.:

int main()
{
  typedef matrix<double,3> matrix_type;
  matrix_type m(/* some initialization */);
  matrix_type::inverter i(matrix);
  if (i.success())
    ; // use i.result()
  else
    ; // do something else
}


> 1.  In the "main()" body of the calling routine that calls the
> matrix class function, I do not seem to be able to create a matrix
> object as part of a structure.  I can create a matrix object (or
> several of them if I wish) in the same "main()" body, but only by
> themselves,not as part of a structure.  I can not assign the matrix
> size in the structure.  I can declare a Matrix<complex> q, but not a
> Matrix<complex> q(3,3), as I can outside of the structure.

Please show us what you are attempting to do and what the compiler has
to say about it.

.