Re: Struct members -> Array elements

wade@stoner.com wrote:
 > kanze wrote:

 >> What's wrong with simply:

 >> class Point3D
 >> {
 >> public:
 >> double getX() const { return coords[ 0 ] ; }
 >> double getY() const { return coords[ 1 ] ; }
 >> double getZ() const { return coords[ 2 ] ; }
 >> double* getXYZ() const { return coords ; }
 >>
 >> // Since you mention STL...
 >> double* begin() const { return coords ; }
 >> double* end() const { return coords + 3 ; }
 >> size_T size() const { return 3 ; }
 >> // ...

 >> private:
 >> double coords[ 3 ] ;
 >> } ;

 >> (or just x(), y(), z() and xyz(), if you prefer).
 >
 > What's wrong:
 > 1) In the debugger, when I look at a Point3D object, it shows
 > me array values, not named values. Not only do I want to see
 > all three values, I want to see all three names.

I take it you avoid std::string as well, because you don't see
it's value as you would expect in the debugger.

But if the semantics are those of named variables, why do you
want the array. There's a contradiction here.

 > 2) Those literal integers are a maintenance issue. Use an
 > enum instead, and you've got a different set of maintenance
 > issues.

I'd say that those literal integers are the definition of x, y
and z. I don't see them as a great problem. And any solution
giving two names to a single object, and trying to keep them in
sync, will create maintenance issues.

 > 3) You need two functions for each array element (one const
 > getter, and one non-const setter).

So?

 > 4) This isn't a POD (although that would be trivial to fix),
 > meaning that any struct or array containing a Point3D is also
 > not a POD.

Remove the private, above, and it is a POD, if that's what is
needed.

--
James Kanze kanze.james@neuf.fr
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