On Fri, Jun 14, 2013 at 7:16 AM, Marc-André Dubois <ma.dub...@me.com> wrote: > Hi guys, > I want to make a subclass of Avogadro::Molecule. Can I do that > kind of association? > > superclass: Molecule > subclass: CustomMolecule
It is possible to subclass Molecule. The XtalOpt extension does this a lot, e.g. https://github.com/dlonie/XtalOpt/blob/stable/src/globalsearch/structure.h > Molecule *parent = gl->molecule(); > CustomMolecule *child = parent; This wouldn't work -- you can't expect the gl->molecule() to be the CustomMolecule type. In C++, the object's type is fixed when it is instantiated -- an object instantiated as a Molecule cannot be used as a CustomMolecule. However, if the "parent" pointer above is actually pointing to an instance of CustomMolecule, you can safely recover the CustomMolecule pointer with: Molecule *mol = gl->molecule(); CustomMolecule *customMol = dynamic_cast<CustomMolecule*>(mol); if (customMol != 0) { ... // do work with customMol pointer. } The dynamic_cast will check if the object pointed to by "mol" is actually an instance of CustomMolecule. If it is, it returns a CustomMolecule* pointer to the object. If it is not, if returns 0. This is how to check if a pointer can be safely downcast into a subclass type. HTH, Dave > (gl is the GLWidget). I know this seems to be an easy question, but I face > some problems and I am not so familiar with C++... Thanks, > > Marc > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Avogadro-devel mailing list > Avogadro-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/avogadro-devel > ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Avogadro-devel mailing list Avogadro-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/avogadro-devel
