forked from mpusz/mp-units
63 lines
2.2 KiB
C++
63 lines
2.2 KiB
C++
/*
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Copyright (c) 2003-2020 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 <mp-units/format.h>
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#include <mp-units/systems/isq/space_and_time.h>
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#include <mp-units/systems/si/unit_symbols.h>
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#include <mp-units/systems/si/units.h>
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#include <iostream>
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#include <type_traits>
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/*
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get conversion factor from one dimensionally equivalent
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quantity type to another
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*/
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namespace {
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template<mp_units::Quantity Target, mp_units::Quantity Source>
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requires std::constructible_from<Target, Source>
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inline constexpr double conversion_factor(Target, Source)
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{
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return (1. * Source::reference).force_numerical_value_in(Target::unit);
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}
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} // namespace
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int main()
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{
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using namespace mp_units;
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using namespace mp_units::si::unit_symbols;
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std::cout << "conversion factor in mp-units...\n\n";
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constexpr auto lengthA = 2.0 * m;
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constexpr auto lengthB = lengthA.in(mm);
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std::cout << MP_UNITS_STD_FMT::format("lengthA( {} ) and lengthB( {} )\n", lengthA, lengthB)
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<< "represent the same length in different units.\n\n";
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std::cout << MP_UNITS_STD_FMT::format("therefore ratio lengthA / lengthB == {}\n\n", lengthA / lengthB);
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std::cout << MP_UNITS_STD_FMT::format("conversion factor from lengthA::unit of {:%q} to lengthB::unit of {:%q}:\n\n",
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lengthA, lengthB)
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<< MP_UNITS_STD_FMT::format("lengthB.value( {} ) == lengthA.value( {} ) * conversion_factor( {} )\n",
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lengthB.numerical_value_ref_in(lengthB.unit),
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lengthA.numerical_value_ref_in(lengthA.unit),
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conversion_factor(lengthB, lengthA));
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}
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