当 n = 3N 时，线程1输出
当 n = 3N + 1 时，线程2输出
当 n = 3N + 2 时，线程3输出

最终的输出为 0、1、2、3、4、5、6、7、8、10

#include <iostream>
#include <thread>
#include <mutex>
#include <condition_variable>
using namespace std;mutex mut;
condition_variable cv;
int N = 0;
void func1() {unique_lock<mutex> lock(mut);while (true) {cv.wait(lock, []{return (N % 3) == 0;});cout << N << endl;N++;cv.notify_all();}
}void func2() {unique_lock<mutex> lock(mut);while (true) {cv.wait(lock, []{return (N % 3) == 1;});cout << N << endl;N++;cv.notify_all();}
}void func3() {unique_lock<mutex> lock(mut);while (true) {cv.wait(lock, []{return (N % 3) == 2;});cout << N << endl;N++;cv.notify_all();}
}int main() {thread t1(func1);thread t2(func2);thread t3(func3);t1.join();t2.join();t3.join();return 0;
}