refactor: first examples refactored for V2

example/box_example.cpp

@@ -0,0 +1,108 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#include <units/format.h>
+#include <units/generic/dimensionless.h>
+#include <units/isq/mechanics.h>
+#include <units/isq/space_and_time.h>
+#include <units/si/constants.h>
+#include <units/si/unit_symbols.h>
+#include <units/si/units.h>
+#include <cassert>
+#include <iostream>
+#include <utility>
+
+namespace {
+
+using namespace units;
+using namespace units::si;
+using namespace units::si::unit_symbols;
+
+inline constexpr auto g = 1 * standard_gravity;
+inline constexpr auto air_density = 1.225 * isq::mass_density[kg / m3];
+
+class Box {
+  quantity<isq::area[m2]> base_;
+  quantity<isq::length[m]> height_;
+  quantity<isq::mass_density[kg / m3]> density_ = air_density;
+public:
+  constexpr Box(const quantity<isq::length[m]>& length, const quantity<isq::length[m]>& width,
+                quantity<isq::length[m]> height) :
+      base_(length * width), height_(std::move(height))
+  {
+  }
+
+  [[nodiscard]] constexpr auto filled_weight() const
+  {
+    const weak_quantity_of<isq::volume> auto volume = base_ * height_;
+    const quantity_of<isq::mass> auto mass = density_ * volume;
+    return mass * g;
+  }
+
+  [[nodiscard]] constexpr quantity<isq::length[m]> fill_level(const quantity<isq::mass[kg]>& measured_mass) const
+  {
+    return height_ * measured_mass * g / filled_weight();
+  }
+
+  [[nodiscard]] constexpr quantity<isq::volume[m3]> spare_capacity(const quantity<isq::mass[kg]>& measured_mass) const
+  {
+    return (height_ - fill_level(measured_mass)) * base_;
+  }
+
+  constexpr void set_contents_density(const quantity<isq::mass_density[kg / m3]>& density_in)
+  {
+    assert(density_in > air_density);
+    density_ = density_in;
+  }
+};
+
+}  // namespace
+
+
+int main()
+{
+  const auto mm = isq::length[unit_symbols::mm];  // helper reference value
+
+  const auto height = (200.0 * mm)[metre];
+  auto box = Box(1000.0 * mm, 500.0 * mm, height);
+  box.set_contents_density(1000.0 * isq::mass_density[kg / m3]);
+
+  const auto fill_time = 200.0 * isq::time[s];      // time since starting fill
+  const auto measured_mass = 20.0 * isq::mass[kg];  // measured mass at fill_time
+  const auto fill_level = box.fill_level(measured_mass);
+  const auto spare_capacity = box.spare_capacity(measured_mass);
+  const auto filled_weight = box.filled_weight();
+
+  const weak_quantity_of<isq::mass_change_rate> auto input_flow_rate = measured_mass / fill_time;
+  const weak_quantity_of<isq::speed> auto float_rise_rate = fill_level / fill_time;
+  const quantity_of<isq::time> auto fill_time_left = (height / fill_level - 1) * fill_time;
+
+  const auto fill_percent = (fill_level / height)[percent];
+
+  std::cout << "mp-units box example...\n";
+  std::cout << STD_FMT::format("fill height at {} = {} ({} full)\n", fill_time, fill_level, fill_percent);
+  std::cout << STD_FMT::format("fill weight at {} = {} ({})\n", fill_time, filled_weight, filled_weight[N]);
+  std::cout << STD_FMT::format("spare capacity at {} = {}\n", fill_time, spare_capacity);
+  std::cout << STD_FMT::format("input flow rate after {} = {}\n", fill_time, input_flow_rate);
+  std::cout << STD_FMT::format("float rise rate = {}\n", float_rise_rate);
+  std::cout << STD_FMT::format("box full E.T.A. at current flow rate = {}\n", fill_time_left);
+}