数据结构（双向链表）（C语言）

利用C语言实现双向链表的基本功能：

• 头文件：

//LinkList.c
#ifndef _LINKLIST_H
#define _LINKLIST_H

#define SUCCESS 10000
#define FAILURE 10001
#define TRUE    10002
#define FALSE   10003

typedef int Elemtype;

typedef struct Node
{
	Elemtype data;
	struct Node *prior;
	struct Node *next;
}Node;

int LinkReverse(Node *head);
int LinkListInit(Node **head);
int LinkInsert(Node *head, int n, Elemtype e);
int LinkTraverse(Node *head, void(*print)(Elemtype));
int LinkLength(Node *head);
int LinkEmpty(Node *head);
int LinkGetelem(Node *head, int n, Elemtype *e);
int LocateElem(Node *head, Elemtype e, int (*p)(Elemtype, Elemtype));
int LinkDelete(Node *head, int n, Elemtype *e);
int LinkClear(Node *head);
int LinkDestory(Node **head);

#endif

功能函数：

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

int LinkReverse(Node *head)
{
	if(NULL == head)
	{
		return FAILURE;
	}
	
	Node *p = head->next, *q;
	head->next = NULL;
	
	while(NULL != p)
	{
		q = p;
		p = p->next;
		q->next = head->next;
		head->next = q;
	}
	return SUCCESS;
}

int LinkListInit(Node **head)
{
	*head = (Node *)malloc(sizeof(Node));
	if(NULL == *head)
	{
		return FAILURE;
	}

	(*head)->next = NULL;
	(*head)->prior = NULL;
	return SUCCESS;
}


int LinkInsert(Node *head, int n, Elemtype e)
{
	int k = 1;
	Node *p = head, *q;
	q = (Node *)malloc(sizeof(Node));

	if(NULL == head)
	{
		return FAILURE;
	}

	while(k < n && NULL != p)
	{
		p = p->next;
		++k;
	}

	if(k > n)
	{
		return FAILURE;
	}

	q->data = e;
	q->next = p->next;
	q->prior = p;
	p->next = q;
	if(NULL != q->next)
	{
		q->next->prior = q;
	}

	return SUCCESS;
}


int LinkTraverse(Node *head, void(*print)(Elemtype))
{
	Node *p = head;
	if(NULL == p)
	{
		return FAILURE;
	}

	while(NULL != p->next)
	{
		p = p->next;
		print(p->data);
	}
	return SUCCESS;
}



int LinkLength(Node *head)
{
	int count = 0;
	if(NULL == head)
	{
		return FAILURE;
	}
	
	Node *p = head->next;

	while(p)
	{
		count++;
		p = p->next;
	}

	return count;
}

int LinkEmpty(Node *head)
{
	if(NULL == head ||NULL ==  head->next)
	{
		return TRUE;
	}
	return FALSE;
}


int LinkGetelem(Node *head, int n, Elemtype *e)
{
	if(NULL == head)
	{
		return FAILURE;
	}

	Node *p = head;
	int i;

	for(i = 0; i < n; i++)
	{
		p = p->next;
	}
	if(!p)
	{
		return FAILURE;
	}

	*e = p->data;
	return SUCCESS;
}

int LocateElem(Node *head, Elemtype e, int (*p)(Elemtype, Elemtype))
{
	if(NULL == head)
	{
		return FAILURE;
	}
	
	Node *q = head;
	int count = 0;
	
	while(q->next)
	{
		q = q->next;
		++count;
		if(TRUE == p(e, q->data))
		{
			return count;
		}
	}
	
	return FAILURE;
}

int LinkDelete(Node *head, int n, Elemtype *e)
{
	if(NULL == head)
	{
		return FAILURE;
	}
	
	int i;
	Node *p = head, *q = head;
	
	for(i = 0; i < n; i++)
	{
		q = p;
		p = p->next;
		if(NULL == p)
		{
			return FAILURE;
		}
	}
	
	*e = p->data;
	q->next = p->next;
	if(NULL != p->next)
	{
		p->next->prior = q;
	}
	else
	{
		q->next = NULL;
	}
	free(p);
	return SUCCESS;
	
}

int LinkClear(Node *head)
{
	if(NULL == head)
	{
		return FAILURE;
	}
	
	Node *p = head->next;
	while(p)
	{
		head->next = p->next;
		p->prior = head;
		free(p);
		p = head->next;
	}
	return SUCCESS;
}

int LinkDestory(Node **head)
{
	if(NULL == head)
	{
		return FAILURE;
	}
	free(*head);
	*head = NULL;
	return SUCCESS;
}

• 测试主函数：

  #include <stdio.h>
  #include <stdlib.h>
  #include <time.h>
  #include "LinkList.h"
  
  void print(Elemtype e)
  {
  	printf("%d ", e);
  }
  
  int cmp(Elemtype e1, Elemtype e2)
  {
  	return (e1 == e2) ? TRUE :FALSE;
  }
  
  
  int main()
  {
  	int ret, i;
  	Node *head = NULL;
  
  	ret = LinkListInit(&head);
  	if(SUCCESS == ret)
  	{
  		printf("Init success.\n");
  	}
  	else
  	{
  		printf("Init failure.\n");
  	}
  
  	srand(time(NULL));
  
  	for(i = 0; i < 8; i++)
  	{
  		ret = LinkInsert(head, i+1, rand()%10);
  		if(SUCCESS == ret)
  		{
  			printf("Insert success.\n");
  		}
  		else
  		{
  			printf("Insert failure.\n");
  		}
  	}
  
  	ret = LinkTraverse(head, print);
  	if(SUCCESS == ret)
  	{
  		printf("Traverse success.\n");
  	}
  	else
  	{
  		printf("Traverse failure.\n");
  	}
  
  	ret = LinkReverse(head);
  	if(SUCCESS == ret)
  	{
  		printf("Reverse success.\n");
  	}
  	else
  	{
  		printf("Reverse failure.\n");
  	}
  	
  	ret = LinkTraverse(head, print);
  	if(SUCCESS == ret)
  	{
  		printf("Traverse success.\n");
  	}
  	else
  	{
  		printf("Traverse failure.\n");
  	}
  	 
  	ret = LinkLength(head);
  	if(FAILURE == ret)
  	{
  		printf("LinkLength failure.\n");
  	}
  	else
  	{
  		printf("Length is %d.\n", ret);
  	}
  
  	ret = LinkEmpty(head);
  	if(TRUE == ret)
  	{
  		printf("LinkList is empty.\n");
  	}
  	else
  	{
  		printf("LinkList isn't empty.\n");
  	}
  
  	int n = 4;
  	Elemtype e;
  	ret = LinkGetelem(head, n, &e);
  	if(SUCCESS == ret)
  	{
  		printf("The %dth is %d.\n", n, e);
  	}
  	else
  	{
  		printf("Get element failure.\n");
  	}
  	
  	ret = LocateElem(head, 9, cmp);
  	if(FAILURE == ret)
  	{
  		printf("9 is not exist.\n");
  	}
  	else
  	{
  		printf("9 is %dth element.\n", ret);
  	}
  	
  	ret = LinkDelete(head, n, &e);
  	if(SUCCESS == ret)
  	{
  		printf("Delete the %dth element %d.\n", n, e);
  	}
  	else
  	{
  		printf("Delete failure.\n");
  	}
  	
  	ret = LinkTraverse(head, print);
  	if(SUCCESS == ret)
  	{
  		printf("Traverse success.\n");
  	}
  	else
  	{
  		printf("Traverse failure.\n");
  	}
  	
  	ret = LinkClear(head);
  	if(SUCCESS == ret)
  	{
  		printf("Clear success.\n");
  	}
  	else
  	{
  		printf("Clear failure.\n");
  	}
  
  	ret = LinkDestory(&head);
  	if(SUCCESS == ret)
  	{
  		printf("Destory success.\n");
  	}
  	else
  	{
  		printf("Destory failure.\n");
  	}
  
  	return 0;
  }