#include <iostream>
#include <thread>
#include <mutex>

using namespace std;

mutex mtx;
int i = 0;
condition_variable cv;
int flag = 0;

void print0()
{
    unique_lock<mutex> ul(mtx);
    while (true)
    {
        while (flag != 0)
        {
            cv.wait(ul);
        }

        flag = 1;
        if (++ i > 100)
        {
            cv.notify_all();
            break;
        }

        cout << "print0: " << i << endl;
        cv.notify_all();
    }
}

void print1()
{
    unique_lock<mutex> ul(mtx);
    while (true)
    {
        while (flag != 1)
        {
            cv.wait(ul);
        }

        flag = 2;
        if (++ i > 100)
        {
            cv.notify_all();
            break;
        }

        cout << "print1: " << i << endl;
        cv.notify_all();
    }
}

void print2()
{
    unique_lock<mutex> ul(mtx);
    while (true)
    {
        while (flag != 2)
        {
            cv.wait(ul);
        }

        flag = 0;
        if (++ i > 100)
        {
            cv.notify_all();
            break;
        }

        cout << "print2: " << i << endl;
        cv.notify_all();
    }
}

int main()
{
    cout << "print 1 ~ 100" << endl;

    thread a(print0);
    thread b(print1);
    thread c(print2);

    a.join();
    b.join();
    c.join();

    return 0;
}