units/example/temperature.cpp

// Boost.Units - A C++ library for zero-overhead dimensional analysis and 
// unit/quantity manipulation and conversion
//
// Copyright (C) 2003-2008 Matthias Christian Schabel
// Copyright (C) 2008 Steven Watanabe
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

/** 
\file
    
\brief temperature.cpp

\detailed
Conversions between Fahrenheit and Kelvin for absolute temperatures and 
temperature differences.

Output:
@verbatim

{ 32 } °F
{ 273.15 } K
{ 273.15 } K
{ 273.15 } K
[ 32 ] °F
[ 17.7778 ] K
[ 17.7778 ] K
[ 17.7778 ] K

@endverbatim
**/

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <sstream>

#include <boost/units/absolute.hpp>
#include <boost/units/get_system.hpp>
#include <boost/units/io.hpp>
#include <boost/units/unit.hpp>
#include <boost/units/quantity.hpp>
#include <boost/units/systems/si/temperature.hpp>
#include <boost/units/detail/utility.hpp>

#include <boost/units/base_units/temperature/fahrenheit.hpp>

using namespace boost::units;

namespace boost {

namespace units {

namespace fahrenheit {

//[temperature_snippet_1
// direct method
//typedef make_system<temperature::fahrenheit_base_unit>::type  system;
//typedef unit<temperature_dimension,system>                    temperature;

// simpler method for single-unit systems
typedef temperature::fahrenheit_base_unit::unit_type	temperature;
typedef get_system<temperature>::type					system;

BOOST_UNITS_STATIC_CONSTANT(degree,temperature);
BOOST_UNITS_STATIC_CONSTANT(degrees,temperature);
//]

} // fahrenheit

//template<>
//struct is_implicitly_convertible<unit<temperature_dimension,fahrenheit::system>,
//                                 unit<temperature_dimension,si::system> > : 
//    public mpl::true_
//{ };

//template<>
//struct is_implicitly_convertible<
//    absolute< unit<temperature_dimension,fahrenheit::system> >,
//    absolute< unit<temperature_dimension,si::system> > > : 
//    public mpl::true_
//{ };

//[temperature_snippet_2
template<>
struct is_implicitly_convertible< 
           fahrenheit::temperature, 
		   si::temperature > : public mpl::true_ { };

template<>
struct is_implicitly_convertible< 
           absolute<fahrenheit::temperature>, 
           absolute<si::temperature> > : public mpl::true_ { };
//]

} // namespace units

} // namespace boost

int main()
{
    std::stringstream sstream1, sstream2;
    
    //[temperature_snippet_3
    quantity<absolute<fahrenheit::temperature> >    T1p(
        32.0*absolute<fahrenheit::temperature>());
    quantity<fahrenheit::temperature>               T1v(
        32.0*fahrenheit::degrees);
    
    quantity<absolute<si::temperature> >            T2p(T1p);
    quantity<absolute<si::temperature> >            T3p = T1p;
    quantity<si::temperature>                       T2v(T1v);
    quantity<si::temperature>                       T3v = T1v;
    //]

    typedef conversion_helper<
        quantity<absolute<fahrenheit::temperature> >,
        quantity<absolute<si::temperature> > >          absolute_conv_type;
    typedef conversion_helper<
        quantity<fahrenheit::temperature>,
        quantity<si::temperature> >                     relative_conv_type;
    
    sstream1  << T1p << std::endl
              << absolute_conv_type::convert(T1p) << std::endl
              << T2p << std::endl
              << T3p << std::endl
              << T1v << std::endl
              << relative_conv_type::convert(T1v) << std::endl
              << T2v << std::endl
              << T3v << std::endl
              << std::endl;
    
    sstream2  << "32 absolute °F" << std::endl
              << "273.15 absolute K" << std::endl
              << "273.15 absolute K" << std::endl
              << "273.15 absolute K" << std::endl
              << "32 °F" << std::endl
              << 17.77777777777 << " K" << std::endl
              << 17.77777777777 << " K" << std::endl
              << 17.77777777777 << " K" << std::endl
              << std::endl;
    
    std::string str1(sstream1.str());
    std::string str2(sstream2.str());

    std::cout << str1;
    
    if(str1 == str2) 
    {
        return(0);
    } 
    else 
    {
        std::cout << std::endl << str2 << std::endl;
        
        if(str1.size() < str2.size()) 
        {
            std::string::iterator iter =
                std::mismatch(str1.begin(), str1.end(), str2.begin()).first;
            
            std::cout << iter - str1.begin() << std::endl;
            std::cout << std::count(str1.begin(), iter, '\n') << std::endl;
        } 
        else 
        {
            std::string::iterator iter =
                std::mismatch(str2.begin(), str2.end(), str1.begin()).first;
            
            std::cout << iter - str2.begin() << std::endl;
            std::cout << std::count(str2.begin(), iter, '\n') << std::endl;
        }
        
        return(-1);
    }
}