数据结构双向循环链表

主程序

#include "fun.h"

int main(int argc, const char *argv[])
{
   double_p H=create_head();
   insert_head(H,10);
   insert_head(H,20);
   insert_head(H,30);
   insert_head(H,40);
   insert_tail(H,50);
   show_link(H);
   del_tail(H);
   show_link(H);
   free_link(H);
   H=NULL;
   show_link(H);


   return 0;
}

源程序

#include "fun.h"

//创建头节点
double_p create_head()
{
   double_p H=(double_p)malloc(sizeof(node));
   if(H==NULL)
   {
       printf("节点申请失败\n");
       return NULL;
   }
   H->prior=H;
   H->next=H;
   H->len=0;
   return H;
}

//创建新节点
double_p create_new(typdata data)
{
   double_p new=(double_p)malloc(sizeof(node));
   if(new==NULL)
   {
       printf("节点申请失败\n");
       return NULL;
   }
   new->prior=NULL;
   new->next=NULL;
   new->data=data;
   return new;
}
//判空
int empty_link(double_p H)
{
   if(H==NULL)
   {
       printf("入参为空，请检查\n");
       return -1;
   }
   return H->len==0;
}
//头插
void insert_head(double_p H,typdata data)
{
   if(H==NULL)
   {
       printf("入参为空，请检查\n");
       return;
   }

   double_p new=create_new(data);
   new->next=H->next;
   H->next=new;
new->next->prior=new;
   new->prior=H;

   H->len++;
}
//遍历
void show_link(double_p H)
{
   if(H==NULL)
   {
       printf("入参为空，请检查\n");
       return;
   }
   if(empty_link(H))
   {
       printf("链表已空，无需遍历\n");
       return;
   }
   double_p p=H;
   while(p->next!=H)
   {
       p=p->next;
       printf("<-%d->",p->data);
   }
   putchar(10);
}
//尾插
void insert_tail(double_p H,typdata data)
{
   if(H==NULL)
   {
       printf("入参为空，请检查\n");
       return;
   }
double_p p=H;
   while(p->next!=H)
   {
       p=p->next;
   }
   double_p new=create_new(data);
   new->next=p->next;
   p->next=new;
   new->prior=p;
   H->prior=new;

H->len++;
}

//尾删
void del_tail(double_p H)
{
   if(H==NULL)
   {
       printf("入参为空，请检查\n");
return;
   }
   if(empty_link(H))
   {
       printf("链表已空，无需删除\n");
       return;
   }

   double_p p=H;
   while(p->next->next!=H)
   {
       p=p->next;
   }
   free(p->next);
   p->next=NULL;
   p->next=H;
H->prior=p;

   H->len--;
}
//释放链表
void free_link(double_p H)
{
   if(H==NULL)
   {
       printf("入参为空，请检查\n");
   }
while(H->next != H)
{
del_tail(H);
}

free(H);
H=NULL;




}

头文件

#ifndef __FUN_H_
#define __FUN_H_

#include <myhead.h>

typedef int typdata;
typedef struct node
{
   union
   {
       typdata data;
       int len;
   };
   struct node * prior;
   struct node *next;
}node,*double_p;

double_p create_head();//创建头节点
double_p create_new(typdata data);//创建新节点
int empty_link(double_p H);//判空
void insert_head(double_p H,typdata data);//头插
void show_link(double_p);//遍历
void insert_tail(double_p H,typdata data);//尾插
void del_tail(double_p H);//尾删
void free_link(double_p H);//释放链表
#endif