PV913circularArrayQueue

#include <iostream>

template <typename ElemT, int sizeP>
class Queue
{
    ElemT storage[sizeP];
    int backPosition;
    int frontPosition;
    int count;
public:
    Queue() : backPosition{ 0 }, frontPosition{ 0 }, count{0} {};
    int size() const { return sizeP; };
    bool empty() const { return count == 0; };
    bool full() const { return count == sizeP; };
    const ElemT& front() const { return storage[frontPosition]; };
    const ElemT& back() const { return backPosition - 1 < 0 ? storage[sizeP - 1] : storage[backPosition-1]; };

    bool push(const ElemT& elem)
    {
        if (!full())
        {
            storage[backPosition] = elem;
            ++backPosition %= sizeP;
            //backPosition = ++backPosition % sizeP;
            ++count;
            return true;
        }
        return false;
    }

    bool pop()
    {
        if (!empty())
        {
            ++frontPosition %= sizeP;
            --count;
            return true;
        }
        return false;
    }

    template <typename ElementType, int size>
    friend std::ostream& operator<<(std::ostream& out, const Queue<ElementType, size>& queue);
};

template <typename ElementType, int size>
std::ostream& operator<<(std::ostream& out, const Queue<ElementType, size>& queue)
{
    if (!queue.empty())
    {
        out << "[ ";
        for (int front{ queue.frontPosition }, cnt{0}; cnt < queue.count; ++front%=queue.size(), ++cnt)
        {
            out << queue.storage[front] << ' ';
        }
        out << " ]\n";
    }
    else
    {
        out << "[empty]\n";
    }
    return out;
};


int main()
{
    Queue<int, 7> queue;
    std::cout << "Queue: " << queue << '\n';

    std::cout << "Pushing into queue..\n";
    for (int i{ 0 }; !queue.full(); ++i)
    {
        queue.push(i);
        std::cout << queue.back() << '\n';
        std::cout << "Queue: " << queue << '\n';
    };

    std::cout << "Popping from queue..\n";
    while (!queue.empty())
    {
        std::cout << queue.front() << ' ';
        queue.pop();
        std::cout << "Queue: " << queue << '\n';
    }

    std::cout << "Queue: " << queue << '\n';
    std::cout << '\n';
    std::cout << queue.front() << ' ';
    std::cout << queue.front() << ' ';

}