#include #include #include #include #include #include //the directive using namespace literals::chrono_literals; is provided by the standard library, so that if a programmer uses using namespace std::chrono; to gain access to the classes in the chrono library, using namespace std::chrono_literals; class Integrator { public: using clock_type = std::chrono::high_resolution_clock; //Class template std::chrono:: duration represents a time interval and gives duration between alarms using dur_t = std::chrono::duration; using func_t = double(*)(double); explicit Integrator(func_t f = nullptr); ~Integrator(); void input(func_t new_input); double output() { return integrate(); } // variable definition private: std::atomic_flag continue_; std::mutex mutex; std::thread worker; func_t func; double state = 0; //Improves precision by reducing sin result error on large values clock_type::time_point const beginning = clock_type::now(); clock_type::time_point t_prev = beginning; //defining of functions void do_work(); double integrate(); }; Integrator::Integrator(func_t f) : func(f) { continue_.test_and_set(); worker = std::thread(&Integrator::do_work, this); } Integrator::~Integrator() { continue_.clear(); worker.join(); } void Integrator::input(func_t new_input) { integrate(); //The class lock_guard is a mutex wrapper that provides a convenient RAII-style mechanism for owning a mutex for the duration of a scoped block. std::lock_guard lock(mutex); func = new_input; } void Integrator::do_work() { while(continue_.test_and_set()) { integrate(); std::this_thread::sleep_for(1ms); } } double Integrator::integrate() { std::lock_guard lock(mutex); auto now = clock_type::now(); dur_t start = t_prev - beginning; dur_t fin = now - beginning; if(func) //couting of state and time state += (func(start.count()) + func(fin.count())) * (fin - start).count() / 2; t_prev = now; return state; } double sine(double time) { constexpr double PI = 3.1415926535897932; return std::sin(2 * PI * 0.5 * time); } int main() { Integrator foo(sine); std::this_thread::sleep_for(2s); foo.input(nullptr); std::this_thread::sleep_for(500ms); std::cout << foo.output(); }

sample 1