//queue.cpp
//methods for class Queue implemented using nodes

#include "queue.h"
#include <stdlib.h>
#include <assert.h>
#include <iostream.h>

Queue::Queue()
{
	front = rear = 0;
}

void Queue::insert(Type d)
{
	Node *node = new Node(d);
	assert(node);
	if (!rear)
		front= node;
	else
		rear->setnext(node);
	rear = node;
}

Type Queue::remove()
{
	assert(!isEmpty());
	Node *node = front;
	Type d = front->getinfo();
	front = front->getnext();
	if (!front)
		rear = 0;
	delete node;
	return d;
}

int Queue::isEmpty()
{
	assert ((front && rear) || (!front && !rear));
	return (!front);
}

Queue::~Queue()
{
	Node *np = front, *nq;
	while (np) {
		nq = np;
		np = np->getnext();
		delete nq;
	}
   front = rear = 0;
}