forked from mpusz/mp-units
63 lines
1.9 KiB
ReStructuredText
63 lines
1.9 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(10q_km / 2 == 5q_km);
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// unit conversions
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static_assert(1q_h == 3600q_s);
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static_assert(1q_km + 1q_m == 1001q_m);
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// dimension conversions
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static_assert(2q_m * 3q_m == 6q_m2);
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static_assert(10q_km / 5q_km == 2);
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static_assert(1000 / 1q_s == 1q_kHz);
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static_assert(1q_km / 1q_s == 1000q_m_per_s);
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static_assert(2q_km_per_h * 2q_h == 4q_km);
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static_assert(2q_km / 2q_km_per_h == 1q_h);
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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 <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(220q_km, 2q_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 << v2 << '\n'; // 70 mi/h
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std::cout << v3 << '\n'; // 31.2928 m/s
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std::cout << v4 << '\n'; // 31 m/s
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}
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.. admonition:: Try it on Compiler Explorer
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`Example #2 <https://godbolt.org/z/f-f6y6>`_
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.. seealso::
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You can find more code examples in the :ref:`Examples` chapter.
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