队列

    头文件：

#ifndef __MYQUEUE_H__#define __MYQUEUE_H__#define ret_val_if_fail(p, val)\  if (!(p)){printf("%s:%d error: "#p" failed.\n", __func__, __LINE__); return val;}#define ret_if_fail(p)\  if (!(p)){printf("%s:%d error: "#p" failed.\n", __func__, __LINE__); return;}struct _MyQueue;typedef struct _MyQueue MyQueue, *MyQueuePtr;MyQueuePtr myqueue_create();void myqueue_destory(MyQueuePtr thiz);int myqueue_empty(MyQueuePtr thiz);void* myqueue_front(MyQueuePtr thiz);void myqueue_pop(MyQueuePtr thiz);void myqueue_push(MyQueuePtr thiz, void* obj);#endif

    实现源文件：

#include <stdio.h>#include <stdlib.h>#include "myqueue.h"typedef struct _QueueNode{  void* data;  struct _QueueNode* next;}QueueNode, *QueueNodePtr;struct _MyQueue{  QueueNodePtr front;  QueueNodePtr back;};MyQueuePtr myqueue_create(){  MyQueuePtr retPtr = (MyQueuePtr)malloc(sizeof(MyQueue));  retPtr->front = (QueueNodePtr)malloc(sizeof(QueueNode));  memset(retPtr->front, 0, sizeof(QueueNode));  retPtr->back = retPtr->front;}void myqueue_destroy(MyQueuePtr thiz){  ret_if_fail(thiz != NULL);  ret_if_fail(thiz->front != NULL);  QueueNodePtr* p = thiz->front;  QueueNodePtr* q = NULL;  while (p != NULL)  {    q = p;    p = p->next;    free(q->data);    free(q);  }  free(thiz);}int myqueue_empty(MyQueuePtr thiz){  ret_val_if_fail(thiz != NULL, 1);// if the queue is not created, then we say it's empty  if (thiz->front == thiz->back)    return 1;  return 0;}void* myqueue_front(MyQueuePtr thiz){  ret_val_if_fail(thiz != NULL, NULL);  ret_val_if_fail(thiz->front != NULL, NULL);  ret_val_if_fail(thiz->front->next != NULL, NULL);  return thiz->front->next->data;}void myqueue_pop(MyQueuePtr thiz){  ret_if_fail(thiz != NULL);  ret_if_fail(thiz->front != NULL);  ret_if_fail(thiz->front->next != NULL);  QueueNodePtr frontNode = thiz->front->next;  if (frontNode->next == NULL)    thiz->back = thiz->front;  thiz->front->next = frontNode->next;  free(frontNode->data);  free(frontNode);}void myqueue_push(MyQueuePtr thiz, void* obj){  ret_if_fail(thiz != NULL);  ret_if_fail(thiz->back != NULL);  QueueNodePtr newPtr = (QueueNodePtr)malloc(sizeof(QueueNode));  newPtr->next = NULL;  newPtr->data = obj;  thiz->back->next = newPtr;  thiz->back = newPtr;}