#include <iostream>
#include <thread>

using namespace std;

class nit {
    enum State { ZAUZETA, ZAVRSILA };
    State s;
    mutex m;
    condition_variable c;

    public:
    nit() : s(ZAUZETA) {};

        void cekaj() {
                unique_lock<mutex> l(m);
                while (s != ZAVRSILA) {
                    c.wait(l);
                }
            }

        void zavrsio() {
            lock_guard<mutex> l(m);
            s = ZAVRSILA;
            c.notify_one();
        }
};

mutex term_mx;
void printA(nit& p) {
   { lock_guard<mutex> l(term_mx);
      cout << "Ja sam nit a!" << endl;
   }
   p.zavrsio();
}

void printB(nit &p) {
   p.cekaj();
   { lock_guard<mutex> l(term_mx);
      cout << "Ja sam nit b!" << endl;
   }
}

int main() {
    nit p;
    thread a,b;

        a = thread(printA, ref(p));
        b = thread(printB, ref(p));

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

    return 0;
}