Of course you can use a unit type that handles conversions AND mathematical operations. Feet to meter cubed and you get m³, and the library will throw a compile error if you try to assign it to anything it doesn't work with (liters would be fine, for example)
> Feet to meter cubed and you get m³, and the library will throw a compile error if you try to assign it to anything it doesn't work with (liters would be fine, for example)
Liters would not be fine if you are using standard floating point values since you lose precision moving decimal points in some cases. Maybe for your application the values are such that this doesn't matter, but without understanding your problem in depth you cannot make the generic statement.
I could write books (I won't but I could) on all the compromises and trade offs in building a unit type library.
News flash, C++ has every conceivable feature, it's the reason why it is so unwieldy. But you can even plug in a fucking GC if you so desire. Let alone stuff like basic meta programming.