#ifndef __CIRCULAR_QUEUE_H__
#define __CIRCULAR_QUEUE_H__

#include <stddef.h>

template<typename T>
class circular_queue
{
public:
    explicit circular_queue(size_t maxsize)
        : maxsize_(maxsize + 1), head_(0), rear_(0)
    {
        array_ = new T[maxsize_];
    }

    circular_queue(size_t maxsize, const T& val)
        : maxsize_(maxsize + 1), head_(0), rear_(0)
    {
        array_ = new T[maxsize_];
        for (size_t i = 0; i != maxsize; ++i)
        {
            array_[i] = val;
        }
        rear_ = maxsize;
    }

    circular_queue(const circular_queue& rhs)
        : maxsize_(rhs.maxsize_), head_(rhs.head_), rear_(rhs.rear_)
    {
        array_ = new T[maxsize_];
        for (int i = 0; i != maxsize_; ++i)
        {
            array_[i] = rhs.array_[i];
        }
    }

    ~circular_queue()
    {
        delete [] array_;
    }

    circular_queue& operator=(const circular_queue& rhs)
    {
        if (this == &rhs)
        {
            return *this;
        }
        delete [] array_;
        maxsize_ = rhs.maxsize_;
        head_ = rhs.head_;
        rear_ = rhs.rear_;
        array_ = new T[maxsize_];
        for (int i = 0; i != maxsize_; ++i)
        {
            array_[i] = rhs.array_[i];
        }
        return *this;
    }

    bool empty() const
    {
        return head_ == rear_;
    }

    size_t size() const
    {
        return (rear_ - head_ + maxsize_) % maxsize_;
    }

    T& front()
    {
        return array_[head_];
    }

    const T& front() const
    {
        return array_[head_];
    }

    void push(const T& val)
    {
        if ((rear_ + 1) % maxsize_ != head_)
        {
            array_[rear_] = val;
            rear_ = (rear_ + 1) % maxsize_;
        }
    }

    void pop()
    {
        if (head_ != rear_)
        {
            head_ = (head_ + 1) % maxsize_;
        }
    }

private:
    size_t  maxsize_;
    int     head_;
    int     rear_;
    T*      array_;
};

#endif