// added some bells and whistles... // from code by Ketan Lalcheta #include #include #include #include #include #include #include #include #include using namespace std; // simplify thread_id string short_id(){ ostringstream ss; ss << this_thread::get_id(); return ss.str().substr(ss.str().size()-3); } //random sleep time (milliseconds) void rand_sleep(int min=1, int max=10){ /* //uniform distribution random algorithm mt19937_64 eng{random_device{}()}; uniform_int_distribution<> dist{1,10}; this_thread::sleep_for( chrono::milliseconds(dist(eng))); */ // or simpler srand alternative srand(time(NULL)); this_thread::sleep_for( chrono::milliseconds(rand()%((max+1)-min)+min)); } class myProducerConsumer { public: // more consumer than producer myProducerConsumer(int producerCount = 3, int consumerCount = 30, int totalToBeProduced = 20) : producerCount(producerCount), consumerCount(consumerCount), totalToBeProduced(totalToBeProduced), curProduced(0), isProductionDone(false) { for(int i=0; i lg(m); q.push(val); cout << "thread#: " << short_id() << " produced: " << val << " q.size: " << q.size() << endl; ++val; ++curProduced; if(curProduced>=totalToBeProduced) { isProductionDone = true; break; } cv.notify_one(); } } void consumer() { //add random delays rand_sleep(); while (true) { unique_lock ul(m); cv.wait(ul, [&]{ return !q.empty()||isProductionDone;}); int val = q.front(); if(!q.empty()) q.pop(); cout << " thread#: " << short_id() << " consumed: " << val << " q.size: " << q.size() << endl; if(q.empty() && isProductionDone) { cv.notify_all(); break; } cv.notify_all(); } } private: queue q; condition_variable cv; mutex m; int producerCount, consumerCount, totalToBeProduced, curProduced; bool isProductionDone; vector producerThreads, consumerThreads; }; int main() { myProducerConsumer obj; return 0; }

producer_consumer