libs/units/example/conversion.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 conversion.cpp
\details
Test explicit and implicit unit conversion.
Output:
@verbatim
//[conversion_output_1
L1 = 2 m
L2 = 2 m
L3 = 2 m
L4 = 200 cm
L5 = 5 m
L6 = 4 m
L7 = 200 cm
//]
//[conversion_output_2
volume (m^3) = 1 m^3
volume (cm^3) = 1e+06 cm^3
volume (m^3) = 1 m^3
energy (joules) = 1 J
energy (ergs) = 1e+07 erg
energy (joules) = 1 J
velocity (2 m/s) = 2 m s^-1
velocity (2 cm/s) = 0.02 m s^-1
//]
@endverbatim
**/
#include <iostream>
#include <boost/units/io.hpp>
#include <boost/units/pow.hpp>
#include <boost/units/systems/cgs.hpp>
#include <boost/units/systems/cgs/io.hpp>
#include <boost/units/systems/si.hpp>
#include <boost/units/systems/si/io.hpp>
using namespace boost::units;
int main()
{
// test quantity_cast
{
// implicit value_type conversions
//[conversion_snippet_1
quantity<si::length> L1 = quantity<si::length,int>(int(2.5)*si::meters);
quantity<si::length,int> L2(quantity<si::length,double>(2.5*si::meters));
//]
//[conversion_snippet_3
quantity<si::length,int> L3 = static_cast<quantity<si::length,int> >(L1);
//]
//[conversion_snippet_4
quantity<cgs::length> L4 = static_cast<quantity<cgs::length> >(L1);
//]
quantity<si::length,int> L5(4*si::meters),
L6(5*si::meters);
quantity<cgs::length> L7(L1);
swap(L5,L6);
std::cout << "L1 = " << L1 << std::endl
<< "L2 = " << L2 << std::endl
<< "L3 = " << L3 << std::endl
<< "L4 = " << L4 << std::endl
<< "L5 = " << L5 << std::endl
<< "L6 = " << L6 << std::endl
<< "L7 = " << L7 << std::endl
<< std::endl;
}
// test explicit unit system conversion
{
//[conversion_snippet_5
quantity<si::volume> vs(1.0*pow<3>(si::meter));
quantity<cgs::volume> vc(vs);
quantity<si::volume> vs2(vc);
quantity<si::energy> es(1.0*si::joule);
quantity<cgs::energy> ec(es);
quantity<si::energy> es2(ec);
quantity<si::velocity> v1 = 2.0*si::meters/si::second,
v2(2.0*cgs::centimeters/cgs::second);
//]
std::cout << "volume (m^3) = " << vs << std::endl
<< "volume (cm^3) = " << vc << std::endl
<< "volume (m^3) = " << vs2 << std::endl
<< std::endl;
std::cout << "energy (joules) = " << es << std::endl
<< "energy (ergs) = " << ec << std::endl
<< "energy (joules) = " << es2 << std::endl
<< std::endl;
std::cout << "velocity (2 m/s) = " << v1 << std::endl
<< "velocity (2 cm/s) = " << v2 << std::endl
<< std::endl;
}
return 0;
}