mirror of
https://github.com/mpusz/mp-units.git
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024f5a9c83
move in,ft,fathom,ft2,ft3,mph from us to international namespace TODO distinguish units with different names for same values
236 lines
7.7 KiB
C++
236 lines
7.7 KiB
C++
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/*
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Copyright (c) 2003-2019 Andy Little.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see http://www.gnu.org/licenses./
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*/
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#include <units/physical/si/length.h>
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#include <units/physical/international/length.h>
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#include <units/physical/us/length.h>
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#include <units/physical/iau/length.h>
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#include <units/physical/typographic/length.h>
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#include <units/physical/imperial/length.h>
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#include <units/physical/si/area.h>
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#include <units/physical/si/volume.h>
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#include <units/physical/si/time.h>
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namespace {
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namespace length{
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template <typename Rep = double>
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using m = units::si::length<units::si::metre,Rep>;
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template <typename Rep = double>
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using mm = units::si::length<units::si::millimetre,Rep>;
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template <typename Rep = double>
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using fm = units::si::length<units::si::femtometre,Rep>;
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template <typename Rep = double>
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using km = units::si::length<units::si::kilometre,Rep>;
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template <typename Rep = double>
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using AU = units::si::length<units::si::astronomical_unit,Rep>;
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template <typename Rep = double>
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using in = units::si::length<units::international::inch,Rep>;
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template <typename Rep = double>
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using angstrom = units::si::length<units::iau::angstrom,Rep>;
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template <typename Rep = double>
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using ch = units::si::length<units::imperial::chain,Rep>;
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template <typename Rep = double>
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using fathom = units::si::length<units::international::fathom,Rep>;
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template <typename Rep = double>
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using fathom_us = units::si::length<units::us::fathom,Rep>;
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template <typename Rep = double>
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using ft = units::si::length<units::international::foot,Rep>;
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template <typename Rep = double>
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using ft_us = units::si::length<units::us::foot,Rep>;
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template <typename Rep = double>
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using ly = units::si::length<units::iau::light_year,Rep>;
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template <typename Rep = double>
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using mi = units::si::length<units::international::mile,Rep>;
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template <typename Rep = double>
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using mi_naut = units::si::length<units::international::nautical_mile,Rep>;
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template <typename Rep = double>
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using pc = units::si::length<units::iau::parsec,Rep>;
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template <typename Rep = double>
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using pica_comp = units::si::length<units::typographic::pica_comp,Rep>;
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template <typename Rep = double>
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using pica_prn = units::si::length<units::typographic::pica_prn,Rep>;
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template <typename Rep = double>
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using point_comp = units::si::length<units::typographic::point_comp,Rep>;
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template <typename Rep = double>
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using point_prn = units::si::length<units::typographic::point_prn,Rep>;
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template <typename Rep = double>
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using rd = units::si::length<units::imperial::rod,Rep>;
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template <typename Rep = double>
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using yd = units::si::length<units::international::yard,Rep>;
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}
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namespace time{
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template <typename Rep = double>
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using s = units::si::time<units::si::second,Rep>;
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template <typename Rep = double>
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using min = units::si::time<units::si::minute,Rep>;
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template <typename Rep = double>
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using h = units::si::time<units::si::hour,Rep>;
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}
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namespace area{
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template <typename Rep = double>
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using m2 = units::si::area<units::si::square_metre,Rep>;
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template <typename Rep = double>
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using fm2 = units::si::area<units::si::square_femtometre,Rep>;
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}
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}
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#include <iostream>
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using namespace units::si::literals;
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using namespace units::international;
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void simple_quantities()
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{
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using distance = length::m<>;
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using time = time::s<>;
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constexpr distance km = 1.0km;
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constexpr distance miles = 1.0mi;
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constexpr time sec = 1s;
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constexpr time min = 1min;
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constexpr time hr = 1h;
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std::cout << "A physical quantities library can choose the simple\n";
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std::cout << "option to provide output using a single type for each base unit:\n\n";
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std::cout << km << '\n';
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std::cout << miles << '\n';
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std::cout << sec << '\n';
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std::cout << min << '\n';
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std::cout << hr << "\n\n";
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}
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void quantities_with_typed_units()
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{
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constexpr length::km<> km = 1km;
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constexpr length::mi<> miles = 1.0mi;
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std::cout.precision(6);
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constexpr time::s<> sec = 1s;
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constexpr time::min<> min = 1min;
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constexpr time::h<> hr = 1h;
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std::cout << "A more flexible option is to provide separate types for each unit,\n\n";
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std::cout << km << '\n';
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std::cout << miles << '\n';
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std::cout << sec << '\n';
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std::cout << min << '\n';
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std::cout << hr << "\n\n";
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constexpr length::m<> meter = 1m;
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std::cout << "then a wide range of pre-defined units can be defined and converted,\n"
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" for consistency and repeatability across applications:\n\n";
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std::cout << meter << '\n' ;
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std::cout << " = " << length::AU<>(meter) << '\n';
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std::cout << " = " << length::angstrom<>(meter) << '\n';
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std::cout << " = " << length::ch<>(meter) << '\n';
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std::cout << " = " << length::fathom<>(meter) << '\n';
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std::cout << " = " << length::fathom_us<>(meter) << '\n';
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std::cout << " = " << length::ft<>(meter) << '\n';
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std::cout << " = " << length::ft_us<>(meter) << '\n';
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std::cout << " = " << length::in<>(meter) << '\n';
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std::cout << " = " << length::ly<>(meter) << '\n';
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std::cout << " = " << length::mi<>(meter) << '\n';
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std::cout << " = " << length::mi_naut<>(meter) << '\n';
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std::cout << " = " << length::pc<>(meter) << '\n';
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std::cout << " = " << length::pica_comp<>(meter) << '\n';
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std::cout << " = " << length::pica_prn<>(meter) << '\n';
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std::cout << " = " << length::point_comp<>(meter) << '\n';
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std::cout << " = " << length::point_prn<>(meter) << '\n';
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std::cout << " = " << length::rd<>(meter) << '\n';
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std::cout << " = " << length::yd<>(meter) << '\n';
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}
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void calcs_comparison()
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{
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std::cout.precision(20);
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std::cout << "\nA distinct unit for each type is efficient and accurate\n"
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"when adding two values of the same very big\n"
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"or very small type:\n\n";
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length::fm<float> L1A = 2fm;
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length::fm<float> L2A = 3fm;
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length::fm<float> LrA = L1A + L2A;
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std::cout << L1A << " + " << L2A << " = " << LrA << "\n\n";
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std::cout << "The single unit method must convert large\n"
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"or small values in other units to the base unit.\n"
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"This is both inefficient and inaccurate\n\n";
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length::m<float> L1B = L1A;
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length::m<float> L2B = L2A;
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length::m<float> LrB = L1B + L2B;
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std::cout << L1B << " + " << L2B << " = " << LrB << "\n\n";
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std::cout << "In multiplication and division:\n\n";
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area::fm2<float> ArA = L1A * L2A ;
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std::cout << L1A << " * " << L2A << " = " << ArA << "\n\n";
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std::cout <<"similar problems arise\n\n";
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area::m2<float> ArB = L1B * L2B;
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std::cout << L1B << " * " << L2B << "\n = " << ArB << '\n';
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}
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int main()
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{
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std::cout << "This demo was originally posted on com.lang.c++.moderated in 2006\n";
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std::cout << "http://compgroups.net/comp.lang.c++.moderated/dimensional-analysis-units/51712\n";
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std::cout << "Here converted to use mpusz/units library.\n\n";
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simple_quantities();
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quantities_with_typed_units();
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calcs_comparison();
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}
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