On Sun, Sep 22, 2013 at 12:38 AM, Robert Ramey
Nathan Crookston wrote:
Hi Robert,
It's a little confusing
it refers to my test case or the units library?
"It" being the units library -- specifically how systems relate to the unit and quantity and determines what's printed.
I concede that I don't get the "system" concept. It's hardly mentioned in the documentation. I sort of had the feeling that all the units had to be part of the same "system" in order to automatically converted.
Yeah, I didn't really get it (I still might not completely get it), but generally conversions are defined in terms of base_units. When you want to store a value as a particular type (as opposed to converting to si units, for example), you need to have a system which can represent that particular type.
hmmm - so this doesn't use the header ? #include
It does, I just moved it up where it could be used by the make_system metafunction.
OK - but now how would I output in meters^3/second ? It seems that the output is coupled to the way the unit is setup. I would have expected that the format of the output display could be delayed until the actual output operation is performed - just like i can on input.
To display in si, you can do what you did before -- create a
consumption_rate_unit based on the si system -- perhaps you could have
a us_consumption_rate and an si_consumption_rate_unit. Usage could be
something like: cout <<
static_cast