#include <iostream>
#include <thread>
#include <mutex>
#include <atomic>
 
static const int num_threads = 10;
 
std::atomic<int> cnt{0}; 
 
//This function will be called from a thread
 
void call_from_thread(int tid) {
    while (cnt!=tid) 
        std::this_thread::yield(); 	
    std::cout << "Launched by thread " << tid << std::endl;
    cnt++; 
}
 
int main() {
    std::thread t[num_threads];
 
    //Launch a group of threads
    for (int i = 0; i < num_threads; ++i) {
        t[i] = std::thread(call_from_thread, i);
    }
 
    std::cout << "Launched from the main\n";
 
    //Join the threads with the main thread
    for (int i = 0; i < num_threads; ++i) {
        t[i].join();
    }
 
    return 0;
}

I2luY2x1ZGUgPGlvc3RyZWFtPgojaW5jbHVkZSA8dGhyZWFkPgojaW5jbHVkZSA8bXV0ZXg+CiNpbmNsdWRlIDxhdG9taWM+CgpzdGF0aWMgY29uc3QgaW50IG51bV90aHJlYWRzID0gMTA7CgpzdGQ6OmF0b21pYzxpbnQ+IGNudHswfTsgCgovL1RoaXMgZnVuY3Rpb24gd2lsbCBiZSBjYWxsZWQgZnJvbSBhIHRocmVhZAoKdm9pZCBjYWxsX2Zyb21fdGhyZWFkKGludCB0aWQpIHsKICAgIHdoaWxlIChjbnQhPXRpZCkgCiAgICAgICAgc3RkOjp0aGlzX3RocmVhZDo6eWllbGQoKTsgCQogICAgc3RkOjpjb3V0IDw8ICJMYXVuY2hlZCBieSB0aHJlYWQgIiA8PCB0aWQgPDwgc3RkOjplbmRsOwogICAgY250Kys7IAp9CgppbnQgbWFpbigpIHsKICAgIHN0ZDo6dGhyZWFkIHRbbnVtX3RocmVhZHNdOwoKICAgIC8vTGF1bmNoIGEgZ3JvdXAgb2YgdGhyZWFkcwogICAgZm9yIChpbnQgaSA9IDA7IGkgPCBudW1fdGhyZWFkczsgKytpKSB7CiAgICAgICAgdFtpXSA9IHN0ZDo6dGhyZWFkKGNhbGxfZnJvbV90aHJlYWQsIGkpOwogICAgfQoKICAgIHN0ZDo6Y291dCA8PCAiTGF1bmNoZWQgZnJvbSB0aGUgbWFpblxuIjsKCiAgICAvL0pvaW4gdGhlIHRocmVhZHMgd2l0aCB0aGUgbWFpbiB0aHJlYWQKICAgIGZvciAoaW50IGkgPSAwOyBpIDwgbnVtX3RocmVhZHM7ICsraSkgewogICAgICAgIHRbaV0uam9pbigpOwogICAgfQoKICAgIHJldHVybiAwOwp9