Re: [Boost-users] getting started with Boost::Units

Subject: Re: [Boost-users] getting started with Boost::Units
From: Mark Volkmann (mark_at_[hidden])
Date: 2009-01-09 15:59:44

On Jan 9, 2009, at 1:16 PM, Matthias Schabel wrote:

>> Thanks!
>>
>> Why does the the following simple code output "605 mi h^-1" instead  
>> of "605 mi/h"? Why is the "^-1" at the end?
>>
>> #include <iostream>
>> #include <boost/units/base_units/us/mile.hpp>
>> #include <boost/units/base_units/metric/hour.hpp>
>> #include <boost/units/io.hpp>
>>
>> using namespace boost::units;
>> using namespace std;
>>
>> typedef us::mile_base_unit::unit_type mile_unit;
>> typedef metric::hour_base_unit::unit_type hour_unit;
>> typedef divide_typeof_helper<mile_unit, hour_unit>::type  
>> miles_per_hour;
>>
>> int main() {
>> quantity<miles_per_hour> mph = 605.0 * miles_per_hour();
>> cout << mph << endl;
>> return 0;
>> }
>
> The output code does not give special status to exponents of -1, but  
> just treats them consistently. If you want specialized output, see  
> examples/composite_output.cpp for an example.

Why is the exponent -1 in this example? I could understand if it was  
zero, but I don't think -1 makes sense.

---
Mark Volkmann