Re: (Probably) easy question about inheritance

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 30 Aug 2007 09:53:38 -0700

Message-ID:

<fb6spl$nf7$1@ihnp4.ucsd.edu>

Patricia Shanahan wrote:

Zerex71 wrote:
...

I'd probably go with definition B. A Vector in my case is a special
form of a matrix. What I also didn't extend my original post to say
was that I would also subclass a Matrix3x3 from Matrix just as I
subclassed a Matrix1x3 from Matrix. I have the need to do
"real" (pure) matrix operations, but saw that in the case of a Vector
that it is really nothing more than a one-dimensional matrix. My
question was mainly about whether there was a way to alias the
underlying members, calling them "array[i]" when accessed via matrix
and "x,y,z" when accessed via vector.

...

It is usually a mistake to directly access variables from outside the
class.

If you went with methods, you could provide getX() and setX as part of
Vector, and array-like access as part of Matrix. You would be free to
store the data in whatever way made most sense, and to change how the
data is stored as you develop your system.

....

Though I would also add that it is probably a mistake to provide any
methods in Matrix that treat it as one dimensional. I would expect the
result of a applying a single index to a Matrix to be a row or column,
not an element of the Matrix.

Patricia