From biermann@mrl.nyu.edu Thu Apr  1 18:35:18 1999
Date: Thu, 1 Apr 1999 18:33:01 -0500 (EST)
From: Henning Biermann <biermann@mrl.nyu.edu>

#include<stdio.h>
#include<stdlib.h>

typedef int ElementType;

typedef struct NodeStruct {
  ElementType elem;
  struct NodeStruct *next;
} NodeType;

NodeType* first = NULL;
NodeType* last = NULL;

int emptyQueue() {
  return (first == NULL);
}

void enqueue(ElementType elem) {
  NodeType* tmpNode;
  tmpNode = malloc(sizeof(NodeType));
  tmpNode->elem = elem;
  tmpNode->next = NULL;

  if (first == NULL) {
    last = first = tmpNode;
  } else {
    last->next = tmpNode;
    last = tmpNode;
  }
}

ElementType dequeue() {
  NodeType* tmpNode;
  tmpNode = first;
  first = first->next;
  return tmpNode->elem;
}

int main() {
  int i;
  int j;
  for (i = 0; i < 10; i++) 
    enqueue(i);

  for (i = 0; i < 5; i++)
    dequeue(i);

  for (i = 10; i < 15; i++)
    enqueue(i);

  while(!emptyQueue()) {
    i = dequeue();
    printf("dequeued:\t%d\n",i);
  }
}