#include #include #include #include struct Node { virtual std::unique_ptr next(bool) = 0; virtual char getType() = 0; }; struct NodeB; struct NodeA : Node { std::unique_ptr next(bool val) override; constexpr char getType() override { return 'A'; } }; struct NodeC : Node { std::unique_ptr next(bool val) override; constexpr char getType() override { return 'C'; } }; struct NodeB : Node { std::unique_ptr next(bool val) override; constexpr char getType() override { return 'B'; } }; class StateMachine { public: void registerNode(std::unique_ptr& node) { m_current = std::move(node); } void registerNode(std::unique_ptr&& node) { m_current = std::move(node); } void update(bool val) { m_current = m_current->next(val); } const std::unique_ptr& getCurrentNode() { return m_current; } private: std::unique_ptr m_current; }; int main() { StateMachine machine; for (int i = 1; i <= 100; ++i) { machine.registerNode(std::unique_ptr(new NodeA())); int j = i; while (j) { machine.update(j & 1); j >>= 1; } if (machine.getCurrentNode()->getType() == 'A') { std::cout << i << ' '; } } return 0; } std::unique_ptr NodeA::next(bool val) { return val ? std::unique_ptr(new NodeB()) : std::unique_ptr(new NodeA()); } std::unique_ptr NodeC::next(bool val) { return val ? std::unique_ptr(new NodeC()) : std::unique_ptr(new NodeB()); } std::unique_ptr NodeB::next(bool val) { return val ? std::unique_ptr(new NodeA()) : std::unique_ptr(new NodeC()); }

Finite State Machine