#include <stdio.h>

#define TRUE 1
#define FALSE 0

typedef int BOOLEAN;

typedef struct CELL *LIST;
struct CELL {
	int element;
	LIST next;
};

typedef struct {
	LIST front, rear;
} QUEUE;

void clear(QUEUE *pQ)
{
	pQ->front = NULL;
}

BOOLEAN isEmpty(QUEUE *pQ)
{
	return (pQ->front == NULL);
}

BOOLEAN isFull(QUEUE *pQ)
{
	return FALSE;
}

BOOLEAN dequeue(QUEUE *pQ, int *px)
{
	if (isEmpty(pQ))
		return FALSE;
	else {
		(*px) = pQ->front->element;
		pQ->front = pQ->front->next;
		return TRUE;
	}
}

BOOLEAN enqueue(int x, QUEUE *pQ)
{
	if (isEmpty(pQ)) {
		pQ->front = (LIST) malloc(sizeof(struct CELL));
		pQ->rear = pQ->front;
	}
	else {
		pQ->rear->next = (LIST) malloc(sizeof(struct CELL));
		pQ->rear = pQ->rear->next;
	}
	pQ->rear->element = x;
	pQ->rear->next = NULL;
	return TRUE;
}