queue.cpp

// queue.cpp -- Queue and Customer methods
#include "queue.h"
#include <cstdlib>

Queue::Queue( int qs ): qsize(qs)
{
	front = rear = NULL;
	items = 0;
}

Queue::~Queue()
{
	Node * temp;
	while (front != NULL) {
		temp = front;
		front = front->next;
		delete temp;
	}
}

bool Queue::isempty() const
{
	return items == 0;
}

bool Queue::isfull() const
{
	return items == qsize;
}

int Queue::queuecount() const
{
	return items;
}

bool Queue::enqueue (const Item & item)
{
	if (isfull()) {
		return false;
	}
	Node * add = new Node;
	if (add == NULL) {
		return false;
	}
	add->item = item;
	add->next = NULL;
	items++;
	if (front == NULL) {
		front = add;
	} else {
		rear->next = add;
	}
	rear = add;
	return true;
}

bool Queue::dequeue ( Item & item )
{
	if (front == NULL) {
		return false;
	}
	item = front->item;
	items--;
	Node * temp = front;
	front = front->next;
	delete temp;
	if (items == 0) {
		rear = NULL;
	}
	return true;
}

void Customer::set (long when)
{	
	processtime = std::rand()%3 + 1;
	arrive = when;
}