Port FluidSim core and scenarios to C++20

include/FluidSim/Solver.hpp

@@ -0,0 +1,24 @@
+#pragma once
+
+#include "FluidSim/Component.hpp"
+#include "FluidSim/Fluid.hpp"
+#include <cstdint>
+#include <vector>
+
+namespace fluidsim::port {
+
+class Solver {
+public:
+    Solver(std::vector<Pipe1D>& pipes, BoundarySystem& boundaries);
+    int minimum_substeps{4};
+    void add_component(Component& component);
+    void step(float dt);
+    std::uint64_t step_count() const { return step_count_; }
+private:
+    std::vector<Pipe1D>& pipes_;
+    BoundarySystem& boundaries_;
+    std::vector<Component*> components_;
+    std::uint64_t step_count_{};
+};
+
+} // namespace fluidsim::port