Atomic read-modify-write test

atomic.cpp

#include <vector>
#include <thread>
#include <atomic>
#include <cassert>

int main()
{
    std::vector<std::thread> threads(16);
    std::atomic<unsigned int> ai(0);

    for (size_t i = 0; i < threads.size(); ++i) {
        threads[i] = std::thread([&ai, i] {
            for (auto j = 0; j < 1000; ++j) {
                ai += i;
            }
        });
    }

    for (auto &t : threads) {
        t.join();
    }

    auto res = 500 * threads.size() * (threads.size() - 1);
    assert(ai == res);
}