From: Terje Slettebø (tslettebo_at_[hidden])
Date: 2003-04-27 17:17:07
>From: "Pavel Vozenilek" <pavel_vozenilek_at_[hidden]>
> "Terje Slettebø" <tslettebo_at_[hidden]> wrote in message
> >From: "Pavel Vozenilek" <pavel_vozenilek_at_[hidden]>
> > I realise that in this case, it may be a lot of functions to define, to
> > define the conversion between any two currencies - for e.g. 20
> > that's around 400 functions to define.
> Not for quantity.hpp. One unit (quantity) there is primary ('privileged')
> and conversions are possible between this and other units. Then it is
> possible to do secondary unit 1 -> primary unit -> secondary unit2
> conversion. This is model of many real systems.
Ah, yes. This was also the reason for my earlier posting, if currencies
could be converted via a "reference value". That would allow one to define
the conversion between N currencies, using just N or 2N (rather than N^2)
factors or conversions.
This could also be done to use units outside SI with SI, by defining
conversion from/to SI, or use SI internally for their representation. This
way, you could do feet * feet, where they either converted to meter before
the multiplication, or used meter as internal representation, and you'd get
an answer as m^2 (or feet^2, if you define a conversion to that).
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk