双向链表实列

最新推荐文章于 2022-11-21 08:54:37 发布

原创最新推荐文章于 2022-11-21 08:54:37 发布 · 593 阅读

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#null #delete #class

本文介绍了一个简单的双向链表实现，包括节点的定义、插入和删除操作等基本功能。

/*双向链表
*易甫 Nightiger (jianan12@gmail.com) Graduate University of Chinese Academy
*/

#include <stdlib.h>

template<class T> class flistnode   //双向链表节点
{
public:
   T data;
   flistnode<T>* next;
   flistnode<T>* prev;
};

template<class T> class flist
{
   flistnode<T>* ptr_head;           //指向链表的头节点
   flistnode<T>* ptr_cur;          //指向当前的节点,实际上有指向末尾节点的意思
   size_t        size;

public:

       void push_cur(T val);       //在当前位置后插入
       void push_head(T val);       //在头节点前置插入
       void pop_cur();
       void pop_head();

       flist(){
           ptr_head=NULL;
           size=0;
       };

       //针赋值为NULL对析构比较总要
       ~flist()
       {
           flistnode<T> * ptr;
           while (ptr_cur->prev!=NULL)
           {
               ptr=ptr_cur;
               ptr_cur=ptr_cur->prev;
               delete ptr;
           }
           delete ptr_head;
           //to free the memory!
       };


};

template<class T> void flist<T>::push_cur(T val)
{
   flistnode<T> * ptr_newnode =new flistnode<T>;
   ptr_newnode->data=val;
   ptr_newnode->next=NULL;
   ptr_newnode->prev=NULL;

   if (ptr_head==NULL)
   {
       ptr_head=ptr_cur=ptr_newnode;
       size++;
   }
   else
   {
       ptr_cur->next=ptr_newnode;   /**/
       ptr_newnode->prev=ptr_cur;   /**/
       ptr_cur=ptr_newnode;       /**/
       size++;
   }
}

template<class T> void flist<T>::push_head(T val)
{
   flistnode<T> * ptr_newnode =new flistnode<T>;
   ptr_newnode->data=val;
   ptr_newnode->next=NULL;
   ptr_newnode->prev=NULL;

   if (ptr_head==NULL)
   {
       ptr_head=ptr_cur=ptr_newnode;
       size++;
   }
   else
   {
       ptr_newnode->next=ptr_head;   /**/
       ptr_head->prev=ptr_newnode;   /**/
       ptr_head=ptr_newnode;       /**/
       size++;
   }
}

template<class T> void flist<T>::pop_cur()
{
   flistnode<T>* ptr_tmp=ptr_cur;
   ptr_cur=ptr_cur->prev;
   ptr_cur->next=NULL;
   delete ptr_tmp;
   size--;

}

template<class T> void flist<T>::pop_head()
{
   flistnode<T>* ptr_tmp = ptr_head;
   ptr_head=ptr_head->next;
   ptr_head->prev=NULL;//This is important
   delete ptr_tmp;
   size--;
}