The basic operation of C-language doubly linked list

Header file #pragma oncetypedef int datatype;typedef struct linklist{datatype _data; Struct linklist* _next;struct linklist* _prev;} Linklist,*plinklist;void initlist (Plinklist pnode);p Linklist _buynode (PLinkList& pNode , datatype x); Void printlist (Plinklist phead); Void pushback (Plinklist& phead, DATATYPE&NBSP;X); Void popback (Plinklist& phead); Void pushfront (PLinkList& pHead, DATATYPE&NBSP;X); Void popfront (Plinklist& phead);p Linklist find (pLinkList pHead,  DATATYPE&NBSP;X); Void insert (plinklist pos,datatype x); Void erase (pLinkList&  Phead, plinklist pos); Void reverse (Plinklist& phead); Void destroylist (pLinkList & phead)///function file #include<stdio.h> #include <assert.h> #include "LinkList.h" #include < malloc.h>//Initialize Void initlist (plinklist pnode) {assert (pnode); if&nBSP; (pnode->_next == null) {pnode->_prev = null;}} Create node Plinklist _buynode (plinklist& pnode, datatype x) {pnode =  (pLinkList) malloc (sizeof (linklist));p node->_data = x;pnode->_next = null;pnode->_prev =  null;return pnode;} Traverse the output List data field Void printlist (Plinklist phead) {plinklist head = phead;if (pHead ==  null) {printf ("The list is empty!\n"); return;} while  (head) {printf ("%d ", head->_data); head = head->_next;} printf ("\ n");} Tail plug Void pushback (plinklist& phead, datatype x) {plinklist head = phead; if  (head == null) {_buynode (phead, x); return;} while  (head->_next) {head = head->_next;} Head->_next = _buynode (head->_next,x); head->_next->_prev = head;} Tail Delete void popback (plinklist& phead) {Plinklist head = phead;plinklist tmp = null;if  (phead == null) {printf ("The linked list is empty!") \ n "); return;} if  (head->_next == null) {free (head);p Head = null;return;} while  (head->_next) {head = head->_next;} Tmp = head->_prev;tmp->_next = null;free (head);} Head plug Void pushfront (plinklist& phead, datatype x) {Plinklist head = phead ;p linklist tmp = phead;if  (phead == null) {_buynode (pHead, x); return;} Phead=_buynode (head->_prev, x);p head->_next = tmp;} Head Delete void popfront (plinklist& phead) {plinklist tmp = phead;if  (pHead ==  null) {printf ("The linked list is empty! \ n "); return;} phead = phead->_next;if  (phead) {phead->_prev = null;} Free (TMP);} Find Plinklist find (plinklist phead, datatype x) {plinklist head = phead; ASSERT (Phead);while  (head) {if  (head->_data == x) Return head;head = head->_next;} Return null;} After inserting _ Void insert (plinklist pos, datatype x) {Plinklist tmp = pos->_next ; assert (POS);     _buynode (pos->_next, x);p os->_next->_prev = pos; Pos->_next->_next = tmp;} Void erase (Plinklist& phead, plinklist pos) {plinklist tmp = pos; ASSERT (POS);if  (pos->_next == null) {pos->_prev->_next = null;free (TMP); return;} if  (pos==phead) {phead = phead->_next;phead->_prev = null;free (POS); return;} Tmp->_prev->_next = tmp->_next;tmp->_next->_prev = tmp->_prev;free (POS);} Reverse Void reverse (plinklist& phead) {plinklist head = phead;plinklist tmp  = pHead;if  (phead == null&&phead->_next == null) return;while   (head) {TMp = head->_next;head->_next = head->_prev;head->_prev = tmp;if  (Head->_prev == null) phead = head;head = tmp;}} Destroy Void destroylist (Plinklist& phead) {while  (phead) {Popfront (phead);}} Test Case    main function # include "LinkList.h" #include <stdio.h>void test1 () {plinklist phead=null;// Pushback (phead, 1);//pushback (phead, 2);//pushback (phead, 3);  //   pushback (phead, 4);//pushback (phead, 5);//printlist (Phead);//popback (Phead);//popback (PHead);//PopBack (PHead );//popback (Phead);//popback (Phead);//popback (Phead); Pushfront (phead, 1); Pushfront (PHEAD,&NBSP;2); Pushfront (phead, 3); Pushfront (PHEAD,&NBSP;4); Pushfront (phead, 5); Printlist (Phead);//popfront (Phead);//popfront (Phead);//popfront (Phead);//popfront (Phead);//popfront (pHead);// Popfront (Phead),//printf ("%d\n", Find (Phead, 6)), Insert (Find (phead, 1),  6); Erase (Phead,find (phead,2)); Printlist (Phead); Reverse (Phead); Printlist (Phead);D estroylist (phead);     printlist (Phead);} Int main () {test1 (); return 0;}

The basic operation of C-language doubly linked list