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#include
#include
#include
#include <condition_variable>
#include
#include
#include

class ThreadPool {
private:
std::mutex queueMutex;
std::condition_variable condition;
bool stop;
std::vectorstd::thread workers;
std::queue<std::function<void()>> tasks;
public:
ThreadPool(size_t num) : stop(false) {
for (size_t i = 0; i < num; i++) {
workers.emplace_back([this]{
for(;;) {
std::unique_lockstd::mutex lock(queueMutex);
condition.wait(lock, [this]{return stop || !tasks.empty();});
if (stop && tasks.empty()) return;
auto task = std::move(tasks.front());
tasks.pop();
lock.unlock();
task();
}
});
}

}

~ThreadPool() {
    std::cout << "~ThreadPool() start\n";
    std::unique_lock<std::mutex> lock(queueMutex);
    stop = true;
    lock.unlock();
    condition.notify_all();
    for (auto& worker : workers)
        worker.join();
    std::cout << "~ThreadPool() end\n";
}

template<class F>
void enqueue(F&& task) {
    std::unique_lock<std::mutex> lock(queueMutex);
    tasks.emplace(std::forward<F>(task));
    lock.unlock();
    condition.notify_one();
    std::cout << "notify thread...\n";
}

};

int main() {
ThreadPool pool(3);

std::cout << "adding tasks\n";
for (int i = 0; i < 15; i++) {
    pool.enqueue([i](){
        std::cout << "Task " << i << " executed by thread " << std::this_thread::get_id() << std::endl;
        std::this_thread::sleep_for(std::chrono::seconds(3));
    });
}
std::cout << "finish adding tasks\n";

std::cout << "This is main thread running\n";

return 0;

}