使用c++ 11实现线程池

以下是使用C++11实现线程池的示例代码：

#include <iostream>
#include <vector>
#include <queue>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>

class ThreadPool {
public:
    ThreadPool(size_t num_threads) {
        for (size_t i = 0; i < num_threads; ++i) {
            threads_.emplace_back([this] {
                while (true) {
                    std::unique_lock<std::mutex> lock(mutex_);
                    condition_.wait(lock, [this] { return !tasks_.empty() || stop_; });
                    if (stop_ && tasks_.empty())
                        return;
                    auto task = std::move(tasks_.front());
                    tasks_.pop();
                    lock.unlock();
                    task();
                }
            });
        }
    }

    ~ThreadPool() {
        {
            std::unique_lock<std::mutex> lock(mutex_);
            stop_ = true;
        }
        condition_.notify_all();
        for (auto& thread : threads_)
            thread.join();
    }

    template<class F>
    void Enqueue(F&& task) {
        {
            std::unique_lock<std::mutex> lock(mutex_);
            tasks_.emplace(std::forward<F>(task));
        }
        condition_.notify_one();
    }

private:
    std::vector<std::thread> threads_;
    std::queue<std::function<void()>> tasks_;
    std::mutex mutex_;
    std::condition_variable condition_;
    bool stop_ = false;
};

int main() {
    ThreadPool pool(4);

    for (int i = 0; i < 8; ++i) {
        pool.Enqueue([i] {
            std::cout << "Task " << i << " is running" << std::endl;
            std::this_thread::sleep_for(std::chrono::seconds(1));
            std::cout << "Task " << i << " is done" << std::endl;
        });
    }

    return 0;
}

此示例实现了一个线程池，其中包含一个任务队列和一组工作线程。构造函数创建指定数量的工作线程，并启动它们以侦听任务队列。Enqueue()方法用于将新任务添加到队列中。每个工作线程将从队列中获取任务并执行它。当线程池被销毁时，所有工作线程都将被停止。