MyObserver(const std::string& name) {

std::cout << "constructing observer " << name << '\n';

}

// set_up is a constructor-like method that will be called exactly once

// passing the number of workers

void set_up(size_t num_workers) override final {

std::cout << "setting up observer with " << num_workers << " workers\n";

}

// on_entry will be called before a worker runs a task

void on_entry(tf::WorkerView wv, tf::TaskView tv) override final {

std::ostringstream oss;

oss << "worker " << wv.id() << " ready to run " << tv.name() << '\n';

std::cout << oss.str();

}

// on_exit will be called after a worker completes a task

void on_exit(tf::WorkerView wv, tf::TaskView tv) override final {

std::ostringstream oss;

oss << "worker " << wv.id() << " finished running " << tv.name() << '\n';

std::cout << oss.str();

}

tf::Executor executor;

// Create a taskflow of eight tasks

tf::Taskflow taskflow;

taskflow.emplace([] () { std::cout << "1\n"; }).name("A");

taskflow.emplace([] () { std::cout << "2\n"; }).name("B");

taskflow.emplace([] () { std::cout << "3\n"; }).name("C");

taskflow.emplace([] () { std::cout << "4\n"; }).name("D");

taskflow.emplace([] () { std::cout << "5\n"; }).name("E");

taskflow.emplace([] () { std::cout << "6\n"; }).name("F");

taskflow.emplace([] () { std::cout << "7\n"; }).name("G");

taskflow.emplace([] () { std::cout << "8\n"; }).name("H");

// create a default observer

std::shared_ptr<MyObserver> observer = executor.make_observer<MyObserver>("MyObserver");

// run the taskflow

executor.run(taskflow).get();

// remove the observer (optional)

executor.remove_observer(std::move(observer));

return 0;