refactor: the rest of the systems refactored for V2

example/clcpp_response.cpp

@@ -0,0 +1,149 @@
+/*
+ Copyright (c) 2003-2019 Andy Little.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see http://www.gnu.org/licenses./
+*/
+
+#include <units/format.h>
+#include <units/iau/iau.h>
+#include <units/imperial/imperial.h>
+#include <units/international/international.h>
+#include <units/isq/space_and_time.h>
+#include <units/quantity_io.h>
+#include <units/si/si.h>
+#include <units/typographic/typographic.h>
+#include <units/usc/usc.h>
+#include <iostream>
+
+namespace {
+
+void simple_quantities()
+{
+  using namespace units;
+  using namespace units::si;
+  using namespace units::international;
+
+  using distance = quantity<isq::distance[kilo<metre>]>;
+  using duration = quantity<isq::duration[second]>;
+
+  constexpr distance km = isq::distance[kilo<metre>](1.0);
+  constexpr distance miles = isq::distance[mile](1.0);
+
+  constexpr duration sec = isq::duration[second](1);
+  constexpr duration min = isq::duration[minute](1);
+  constexpr duration hr = isq::duration[hour](1);
+
+  std::cout << "A physical quantities library can choose the simple\n";
+  std::cout << "option to provide output using a single type for each base unit:\n\n";
+  std::cout << km << '\n';
+  std::cout << miles << '\n';
+  std::cout << sec << '\n';
+  std::cout << min << '\n';
+  std::cout << hr << "\n\n";
+}
+
+void quantities_with_typed_units()
+{
+  using namespace units;
+  using namespace units::si;
+  using namespace units::international;
+
+  constexpr auto km = isq::distance[kilo<metre>](1.0);
+  constexpr auto miles = isq::distance[mile](1.0);
+
+  std::cout.precision(6);
+
+  constexpr auto sec = isq::duration[second](1);
+  constexpr auto min = isq::duration[minute](1);
+  constexpr auto hr = isq::duration[hour](1);
+
+  std::cout << "A more flexible option is to provide separate types for each unit,\n\n";
+  std::cout << km << '\n';
+  std::cout << miles << '\n';
+  std::cout << sec << '\n';
+  std::cout << min << '\n';
+  std::cout << hr << "\n\n";
+
+  constexpr quantity<isq::length[metre]> meter{1};
+  std::cout << "then a wide range of pre-defined units can be defined and converted,\n"
+               " for consistency and repeatability across applications:\n\n";
+
+  std::cout << meter << '\n';
+
+  std::cout << " = " << meter[astronomical_unit] << '\n';
+  std::cout << " = " << meter[iau::angstrom] << '\n';
+  std::cout << " = " << meter[imperial::chain] << '\n';
+  std::cout << " = " << meter[imperial::fathom] << '\n';
+  std::cout << " = " << meter[usc::fathom] << '\n';
+  std::cout << " = " << meter[international::foot] << '\n';
+  std::cout << " = " << meter[usc::survey1893::us_survey_foot] << '\n';
+  std::cout << " = " << meter[international::inch] << '\n';
+  std::cout << " = " << meter[iau::light_year] << '\n';
+  std::cout << " = " << meter[international::mile] << '\n';
+  std::cout << " = " << meter[international::nautical_mile] << '\n';
+  std::cout << " = " << meter[iau::parsec] << '\n';
+  std::cout << " = " << meter[typographic::pica_dtp] << '\n';
+  std::cout << " = " << meter[typographic::pica_us] << '\n';
+  std::cout << " = " << meter[typographic::point_dtp] << '\n';
+  std::cout << " = " << meter[typographic::point_us] << '\n';
+  std::cout << " = " << meter[imperial::rod] << '\n';
+  std::cout << " = " << meter[international::yard] << '\n';
+}
+
+void calcs_comparison()
+{
+  using namespace units;
+  using namespace units::si::unit_symbols;
+
+  std::cout << "\nA distinct unit for each type is efficient and accurate\n"
+               "when adding two values of the same very big\n"
+               "or very small type:\n\n";
+
+  const auto L1A = isq::length[fm](2.f);
+  const auto L2A = isq::length[fm](3.f);
+  const auto LrA = L1A + L2A;
+  std::cout << STD_FMT::format("{:%.30Q %q}\n + {:%.30Q %q}\n   = {:%.30Q %q}\n\n", L1A, L2A, LrA);
+
+  std::cout << "The single unit method must convert large\n"
+               "or small values in other units to the base unit.\n"
+               "This is both inefficient and inaccurate\n\n";
+
+  const auto L1B = L1A[m];
+  const auto L2B = L2A[m];
+  const auto LrB = L1B + L2B;
+  std::cout << STD_FMT::format("{:%.30eQ %q}\n + {:%.30eQ %q}\n   = {:%.30eQ %q}\n\n", L1B, L2B, LrB);
+
+  std::cout << "In multiplication and division:\n\n";
+
+  const quantity<isq::area[square<fm>], float> ArA = L1A * L2A;
+  std::cout << STD_FMT::format("{:%.30Q %q}\n * {:%.30Q %q}\n   = {:%.30Q %q}\n\n", L1A, L2A, ArA);
+
+  std::cout << "similar problems arise\n\n";
+
+  const quantity<isq::area[m2], float> ArB = L1B * L2B;
+  std::cout << STD_FMT::format("{:%.30eQ %q}\n * {:%.30eQ %q}\n   = {:%.30eQ %q}\n\n", L1B, L2B, ArB);
+}
+
+}  // namespace
+
+int main()
+{
+  std::cout << "This demo was originally posted on com.lang.c++.moderated in 2006\n";
+  std::cout << "https://groups.google.com/g/comp.lang.c++.moderated/c/upv7hZExtf4/m/XruKUk8LhXYJ\n";
+  std::cout << "Here converted to use mp-units library.\n\n";
+
+  simple_quantities();
+  quantities_with_typed_units();
+  calcs_comparison();
+}