NSUnit is an abstract class that declares a programmatic interface for objects that represent a unit of measure.
- iOS 10.0+
- macOS 10.12+
- tvOS 10.0+
- watchOS 3.0+
Dimension subclass is an abstract class that represents a dimensional unit, which can be converted into different units of the same type. The Foundation framework provides several concrete
Dimension subclasses to represent the most common physical quantities, including mass, length, duration, and speed.