public:

Queue( int capacity = defaultQueueCapacity )

: _capacity { capacity }, _count { 0 },

_head { 0 }, _tail { -1 }, _elements { new T[_capacity] }

{

}

bool empty() const

{

return ( _count == 0 );

}

int count() const

{

return _count;

}

int capacity() const

{

return _capacity;

}

void pop()

{

if (empty())

{

return;

}

else {

--_count;

++_head;

if ( _head == _capacity ) {

_head = 0;

}

}

}

bool push( const T & obj )

{

if ( _count == _capacity )

{

return false;

}

else {

++_count;

++_tail;

if ( _tail == _capacity )

{

_tail = 0;

}

_elements[_tail] = obj;

return true;

}

}

const T & front() const

{

if ( empty() ) throw empty_queue_exception;

return _elements[_head];

}

private:

class EmptyQueueException : public std::exception {

virtual const char * what() const throw()

{

return "Queue is empty";

}

} empty_queue_exception;

int _capacity;

int _count;

int _head;

int _tail;

T * _elements;

Queue( const Queue & );

Queue & operator= ( const Queue & );