Compiler Explorer

Source code

#include <mp-units/format.h>
#include <mp-units/ostream.h>
#include <mp-units/systems/isq.h>
#include <mp-units/systems/si.h>
#include <iosfwd>
#include <print>

using namespace mp_units;
using namespace mp_units::si::unit_symbols;

constexpr struct amsterdam_sea_level : absolute_point_origin<amsterdam_sea_level, isq::altitude> {
} amsterdam_sea_level;

constexpr struct mediterranean_sea_level : relative_point_origin<amsterdam_sea_level - 27 * cm> {
} mediterranean_sea_level;

using altitude_DE = quantity_point<isq::altitude[m], amsterdam_sea_level>;
using altitude_CH = quantity_point<isq::altitude[m], mediterranean_sea_level>;

template<auto R, typename Rep>
std::ostream& operator<<(std::ostream& os, quantity_point<R, altitude_DE::point_origin, Rep> alt)
{
  return os << alt.quantity_ref_from(altitude_DE::point_origin) << " AMSL(DE)";
}

template<auto R, typename Rep>
std::ostream& operator<<(std::ostream& os, quantity_point<R, altitude_CH::point_origin, Rep> alt)
{
  return os << alt.quantity_ref_from(altitude_CH::point_origin) << " AMSL(CH)";
}

template<auto R, typename Rep>
struct std::formatter<quantity_point<R, altitude_DE::point_origin, Rep>> : formatter<quantity<R, Rep>> {
  template<typename FormatContext>
  auto format(const quantity_point<R, altitude_DE::point_origin, Rep>& alt, FormatContext& ctx) const
  {
    formatter<quantity<R, Rep>>::format(alt.quantity_ref_from(altitude_DE::point_origin), ctx);
    return std::format_to(ctx.out(), " AMSL(DE)");
  }
};

template<auto R, typename Rep>
struct std::formatter<quantity_point<R, altitude_CH::point_origin, Rep>> : formatter<quantity<R, Rep>> {
  template<typename FormatContext>
  auto format(const quantity_point<R, altitude_CH::point_origin, Rep>& alt, FormatContext& ctx) const
  {
    formatter<quantity<R, Rep>>::format(alt.quantity_ref_from(altitude_CH::point_origin), ctx);
    return std::format_to(ctx.out(), " AMSL(CH)");
  }
};

int main()
{
  // expected bridge altitude in a specific reference system
  quantity_point expected_bridge_alt = amsterdam_sea_level + 330 * m;

// some nearest landmark altitudes on both sides of the river
  // equal but not equal ;-)
  altitude_DE landmark_alt_DE = altitude_DE::point_origin + 300 * m;
  altitude_CH landmark_alt_CH = altitude_CH::point_origin + 300 * m;

// artifical deltas from landmarks of the bridge base on both sides of the river
  quantity delta_DE = isq::height(3 * m);
  quantity delta_CH = isq::height(-2 * m);

// artificial altitude of the bridge base on both sides of the river
  quantity_point bridge_base_alt_DE = landmark_alt_DE + delta_DE;
  quantity_point bridge_base_alt_CH = landmark_alt_CH + delta_CH;

// artificial height of the required bridge pilar height on both sides of the river
  quantity bridge_pilar_height_DE = expected_bridge_alt - bridge_base_alt_DE;
  quantity bridge_pilar_height_CH = expected_bridge_alt - bridge_base_alt_CH;

std::println("Bridge pillars height:");
  std::println("- Germany:     {}", bridge_pilar_height_DE);
  std::println("- Switzerland: {}", bridge_pilar_height_CH);

// artificial bridge altitude on both sides of the river in both systems
  quantity_point bridge_road_alt_DE = bridge_base_alt_DE + bridge_pilar_height_DE;
  quantity_point bridge_road_alt_CH = bridge_base_alt_CH + bridge_pilar_height_CH;

std::println("Bridge road altitude:");
  std::println("- Germany:     {}", bridge_road_alt_DE);
  std::println("- Switzerland: {}", bridge_road_alt_CH);

std::println("Bridge road altitude relative to the Amsterdam Sea Level:");
  std::println("- Germany:     {}", bridge_road_alt_DE.quantity_from(amsterdam_sea_level));
  std::println("- Switzerland: {}", bridge_road_alt_CH.quantity_from(amsterdam_sea_level));
}