forked from mpusz/mp-units
Mateusz Pusz
9527b39005
We had some fun exploring the STD UDLs for potential collisions, we have learnt our lesson and know how to proceed. Now is high time to start behaving and obeying C++ rules.
67 lines
2.1 KiB
ReStructuredText
67 lines
2.1 KiB
ReStructuredText
Quick Start
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===========
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Here is a small example of possible operations::
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// simple numeric operations
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static_assert(10_q_km / 2 == 5_q_km);
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// unit conversions
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static_assert(1_q_h == 3600_q_s);
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static_assert(1_q_km + 1_q_m == 1001_q_m);
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// dimension conversions
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static_assert(1_q_km / 1_q_s == 1000_q_m_per_s);
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static_assert(2_q_km_per_h * 2_q_h == 4_q_km);
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static_assert(2_q_km / 2_q_km_per_h == 1_q_h);
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static_assert(2_q_m * 3_q_m == 6_q_m2);
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static_assert(10_q_km / 5_q_km == 2);
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static_assert(1000 / 1_q_s == 1_q_kHz);
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.. admonition:: Try it on Compiler Explorer
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`Example #1 <https://godbolt.org/z/XPmjPz>`_
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This library requires some C++20 features (concepts, classes as
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:abbr:`NTTP (Non-Type Template Parameter)`, ...). Thanks to them the user gets a powerful
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but still easy to use interface where all unit conversions and dimensional analysis can be
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performed without sacrificing on accuracy. Please see the below example for a quick preview
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of basic library features::
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#include <units/physical/si/speed.h>
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#include <units/physical/international/speed.h>
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#include <units/format.h>
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#include <iostream>
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using namespace units::physical;
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constexpr Speed auto avg_speed(Length auto d, Time auto t)
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{
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return d / t;
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}
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int main()
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{
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using namespace units::physical::si::literals;
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Speed auto v1 = avg_speed(220_q_km, 2_q_h);
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Speed auto v2 = avg_speed(si::length<international::mile>(140), si::time<si::hour>(2));
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Speed auto v3 = quantity_cast<si::metre_per_second>(v2);
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Speed auto v4 = quantity_cast<int>(v3);
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std::cout << v1 << '\n'; // 110 km/h
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std::cout << fmt::format("{}", v2) << '\n'; // 70 mi/h
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std::cout << fmt::format("{:%Q in %q}", v3) << '\n'; // 31.2928 in m/s
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std::cout << fmt::format("{:%Q}", v4) << '\n'; // 31
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}
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.. admonition:: Try it on Compiler Explorer
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`Example #2 <https://godbolt.org/z/xE91TY>`_
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.. seealso::
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You can find more code examples in the :ref:`Examples` chapter.
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