Problem Solving with Algorithms and Data Structures using C++: The PreTeXt Interactive Edition

class Printer {
public:
    Printer(int pagesPerMinute) {
        pagerate = pagesPerMinute;
        timeRemaining=0;
        working = false;
    }

    void tick() {
        //Performed once per second in the simulation.

        if (working) { // If we're working on something...
            timeRemaining--;// Subtract the remaining time.
            if (timeRemaining <= 0)
                working = false; // When finished, stop working.
        }
    }

    bool busy() {
        return working;
    }

    void startNext(Task newtask) {
        currentTask=newtask;
        timeRemaining=newtask.getPages()*60/pagerate;
        working = true;
    }

private:
    int pagerate; // unit is pages per minute.
    Task currentTask = {0};// Current task. default is a dummy value.
    bool working; // Are we working on the current task?
    int timeRemaining; // Time remaining, in "seconds".
};

class Task {
public:
    Task(int time) {
        timestamp = time;
        pages=(rand()%20) + 1;
    }

    int getStamp() {
        return timestamp;
    }

    int getPages() {
        return pages;
    }

    int waitTime(int currenttime) {
        return (currenttime - timestamp);
    }
private:
    int timestamp;
    int pages;
};

void simulation(int numSeconds, int pagesPerMinute) {
    Printer labprinter(pagesPerMinute);

    //The Queue ADT from the standard container library.
    queue<Task> printQueue;

    //A vector of wait-times for each task.
    vector<int> waitingTimes;

    //For every second in the simulation...
    for (int i = 0; i < numSeconds; i++) {

        //If there's a new printing task, add it to the queue.
        if (newPrintTask()) {
            Task task(i);//Create it...
            printQueue.push(task);//Push it.
        }

        //If the printer is not busy and the queue is not empty:
        if (!labprinter.busy() &&!printQueue.empty()) {
            Task nextTask = printQueue.front(); // Assign a new task from the queue.
            printQueue.pop(); // Remove it from the front

            //Add the estimated wait time to our vector.
            waitingTimes.push_back(nextTask.waitTime(i));
            labprinter.startNext(nextTask);
        }

        //Process the current task.
        labprinter.tick();
    }

    //Average out every wait time for the simulation.
    float total=0;
    for (int waitTime : waitingTimes)
        total += waitTime;

    cout << "Average Wait "<<total/waitingTimes.size()<<" secs "<<printQueue.size()<<" tasks remaining."<<endl;
}