如何同步整数数组的单个元素？

#include<iostream>
#include<vector>
#include<atomic>
#include<thread>

int main() {
    const int n = 100000;
    std::vector<std::atomic<int>> arr(n);

    // 初始化数组
    for (int i = 0; i < n; ++i) {
        arr[i].store(0);
    }

    // 创建线程并行操作数组
    const int num_threads = 4;
    std::vector<std::thread> threads(num_threads);
    for (int t = 0; t < num_threads; ++t) {
        threads[t] = std::thread([&](int thread_id) {
            for (int i = 0; i < n; ++i) {
                // 原子地增加数组元素的值
                arr[i].fetch_add(1, std::memory_order_relaxed);
            }
        }, t);
    }

    // 等待所有线程完成
    for (auto& t : threads) {
        t.join();
    }

    // 检查数组元素的值
    for (int i = 0; i < n; ++i) {
        std::cout << "arr[" << i << "] = "<< arr[i].load()<< std::endl;
    }

    return 0;
}