From 64248c0752eb92da84f8733f4fcf6dcd980344a1 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Sun, 23 Feb 2020 17:40:18 +0100
Subject: [PATCH] Total energy example added

---
 example/CMakeLists.txt   |  1 +
 example/total_energy.cpp | 74 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)
 create mode 100644 example/total_energy.cpp

diff --git a/example/CMakeLists.txt b/example/CMakeLists.txt
index acab5452..3dbfb34b 100644
--- a/example/CMakeLists.txt
+++ b/example/CMakeLists.txt
@@ -28,6 +28,7 @@ endfunction()
 add_example(avg_velocity)
 add_example(hello_units)
 add_example(measurement)
+add_example(total_energy)
 add_example(unknown_dimension)
 add_example(box_example)
 add_example(capacitor_time_curve)
diff --git a/example/total_energy.cpp b/example/total_energy.cpp
new file mode 100644
index 00000000..79fab5cd
--- /dev/null
+++ b/example/total_energy.cpp
@@ -0,0 +1,74 @@
+// 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/physical/si/energy.h>
+#include <units/physical/si/momentum.h>
+#include <units/physical/si/velocity.h>
+#include <units/physical/si/constants.h>
+#include <units/math.h>
+#include <iostream>
+
+namespace {
+
+using namespace units;
+
+Energy auto total_energy(Momentum auto p, Mass auto m, Velocity auto c)
+{
+  return sqrt(pow<2>(p * c) + pow<2>(m * pow<2>(c)));
+}
+
+void example()
+{
+  using namespace si;
+
+  const Momentum auto p = 4.q_GeV / speed_of_light;
+  const momentum<kilogram_metre_per_second> p_si = p;
+  const Mass auto m = 3.q_GeV / pow<2>(speed_of_light);
+  const mass<kilogram> m_si = m;
+  const Velocity auto c = speed_of_light;
+  const Energy auto E = total_energy(p, m, c);
+  const energy<joule> E_si = total_energy(p_si, m_si, c);
+
+  std::cout << "p = " << p << "\n"
+            << "p_si = " << p_si << "\n"
+            << "m = " << m << "\n"
+            << "m_si = " << m_si << "\n"
+            << "c = " << c << "\n"
+            << "E = " << E << "\n"
+            << "E_si = " << E_si << "\n"
+            << "E_GeV = " << quantity_cast<gigaelectronvolt>(E_si) << "\n";
+}
+
+} // namespace
+
+int main()
+{
+  try {
+    example();
+  }
+  catch (const std::exception& ex) {
+    std::cerr << "Unhandled std exception caught: " << ex.what() << '\n';
+  }
+  catch (...) {
+    std::cerr << "Unhandled unknown exception caught\n";
+  }
+}