1. 18.5 Linked Queues
Like a stack, a queue can be implemented using pointers and nodes
Allows dynamic sizing, avoids issue of wrapping indices
NULL
front
rear
Chapter 18 slide 1

2. Implementation Data Structures
class QNode {
char value;
QNode *next;
QNode(char ch, QNode *p = 0);
{value = ch; next = p;} }
QNode *front = NULL;
QNode *rear = NULL;
Chapter 18 slide 2

3. isEmpty Member Function
To check if queue is empty:
bool isEmpty() {
if (front == NULL)
return true;
else
return false; }
See DynIntQueue.h, DynIntQueue.cpp, pr18-06.cpp
Chapter 18 slide 3

4. enqueue Member Function
To add item at rear of queue
void enqueue(char x) {
if (isEmpty())
{ rear = new QNode(x);
front = rear;
return; }
rear->next = new QNode(x);
rear = rear->next;
See DynIntQueue.h, DynIntQueue.cpp, pr18-06.cpp
Chapter 18 slide 4

5. dequeue Member Function
To remove item from front of queue
void dequeue(char &x) {
if (!isEmpty())
x = front->value;
QNode *oldfront = front;
front = front->next;
delete oldfront; }
See DynIntQueue.h, DynIntQueue.cpp, pr18-06.cpp
Chapter 18 slide 5