Quantitified type representing scientific quantities, i.e. quantities expressed as a
magnitude and units. Units were inspired by the Unified Code for Units of Measure
(UCUM), developed by Gunther Schadow and Clement J. McDonald of The Regenstrief
Institute.
Can also be used for time durations, where it is more convenient to treat these as
simply a number of seconds rather than days, months, years.

Declaration :

• C++ : class DV_QUANTITY : public DV_AMOUNT
• Java : package class DV_QUANTITY extends DV_AMOUNT

Artifact : DV_QUANTITY

All public operations : is_integral , is_normal , is_simple , is_strictly_comparable_to , operator+ , operator- , operator< , operator= , valid_magnitude_status , valid_percentage