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

using namespace std;

mutex mtx;
int flag = 0;
condition_variable cv;

void printA()
{
    unique_lock<mutex> ul(mtx);
    int cntA = 0;
    while (cntA < 10)
    {
        while (flag != 0)
        {
            cv.wait(ul);
        }
        cout << "print A " << cntA + 1 << " times" << endl;
        flag = 1;
        cntA ++;
        cv.notify_all();
    }
}

void printB()
{
    unique_lock<mutex> ul(mtx);
    int cntB = 0;
    while (cntB < 10)
    {
        while (flag != 1)
        {
            cv.wait(ul);
        }
        cout << "print B " << cntB + 1 << " times" << endl;
        flag = 2;
        cntB ++;
        cv.notify_all();
    }
}

void printC()
{
    unique_lock<mutex> ul(mtx);
    int cntC = 0;
    while (cntC < 10)
    {
        while (flag != 2)
        {
            cv.wait(ul);
        }
        cout << "print C " << cntC + 1 << " times" << endl;
        flag = 0;
        cntC ++;
        cv.notify_all();
    }
}

int main()
{
    thread a(printA);
    thread b(printB);
    thread c(printC);

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

    return 0;
}