C语言数据结构 双向链表的建立与基本操作

pinsert->prior=p;pinsert->next=p->next;p->next->prior=pinsert;p->next=pinsert;  

 p->prior->next=p->next;  p->next->prior=p->prior;  free(p);

#include<stdio.h>#include<stdlib.h>#include<time.h>#define OK 1#define ERROR 0#define TRUE 1#define FALSE 0typedef int status;typedef int elemtype;typedef struct node{  elemtype data;  struct node * next;  struct node * prior;}node;typedef struct node* dlinklist;status visit(elemtype c){  printf("%d ",c);}/*双向链表初始化*/status initdlinklist(dlinklist * head,dlinklist * tail){  (*head)=(dlinklist)malloc(sizeof(node));  (*tail)=(dlinklist)malloc(sizeof(node));  if(!(*head)||!(*tail))    return ERROR;  /*这一步很关键*/   (*head)->prior=NULL;  (*tail)->next=NULL;  /*链表为空时让头指向尾*/  (*head)->next=(*tail);  (*tail)->prior=(*head);}/*判定是否为空*/status emptylinklist(dlinklist head,dlinklist tail){  if(head->next==tail)    return TRUE;  else    return FALSE;} /*尾插法创建链表*/ status createdlinklisttail(dlinklist head,dlinklist tail,elemtype data){  dlinklist pmove=tail,pinsert;  pinsert=(dlinklist)malloc(sizeof(node));  if(!pinsert)     return ERROR;  pinsert->data=data;  pinsert->next=NULL;  pinsert->prior=NULL;  tail->prior->next=pinsert;  pinsert->prior=tail->prior;  pinsert->next=tail;  tail->prior=pinsert;} /*头插法创建链表*/ status createdlinklisthead(dlinklist head,dlinklist tail,elemtype data){  dlinklist pmove=head,qmove=tail,pinsert;  pinsert=(dlinklist)malloc(sizeof(node));  if(!pinsert)    return ERROR;  else{    pinsert->data=data;    pinsert->prior=pmove;    pinsert->next=pmove->next;    pmove->next->prior=pinsert;    pmove->next=pinsert;  }}/*正序打印链表*/ status traverselist(dlinklist head,dlinklist tail){  /*dlinklist pmove=head->next;  while(pmove!=tail){    printf("%d ",pmove->data);    pmove=pmove->next;  }  printf("/n");  return OK;*/  dlinklist pmove=head->next;  while(pmove!=tail){    visit(pmove->data);    pmove=pmove->next;  }  printf("/n");}/*返回第一个值为data的元素的位序*/status locateelem(dlinklist head,dlinklist tail,elemtype data){  dlinklist pmove=head->next;  int pos=1;  while(pmove&&pmove->data!=data){    pmove=pmove->next;    pos++;  }  return pos;}/*返回表长*/status listlength(dlinklist head,dlinklist tail){  dlinklist pmove=head->next;  int length=0;  while(pmove!=tail){    pmove=pmove->next;    length++;  }  return length;}/*逆序打印链表*/status inverse(dlinklist head,dlinklist tail){  dlinklist pmove=tail->prior;  while(pmove!=head){    visit(pmove->data);    pmove=pmove->prior;  }  printf("/n");}/*删除链表中第pos个位置的元素，并用data返回*/status deleteelem(dlinklist head,dlinklist tail,int pos,elemtype *data){  int i=1;  dlinklist pmove=head->next;  while(pmove&&i<pos){    pmove=pmove->next;    i++;  }  if(!pmove||i>pos){    printf("输入数据非法/n");    return ERROR;  }  else{    *data=pmove->data;    pmove->next->prior=pmove->prior;    pmove->prior->next=pmove->next;    free(pmove);  }}/*在链表尾插入元素*/status inserttail(dlinklist head,dlinklist tail,elemtype data){  dlinklist pinsert;  pinsert=(dlinklist)malloc(sizeof(node));  pinsert->data=data;  pinsert->next=NULL;  pinsert->prior=NULL;  tail->prior->next=pinsert;  pinsert->prior=tail->prior;  pinsert->next=tail;  tail->prior=pinsert;  return OK;} int main(void){  dlinklist head,tail;  int i=0;  elemtype data=0;  initdlinklist(&head,&tail);  if(emptylinklist(head,tail))    printf("链表为空/n");  else    printf("链表不为空/n");  printf("头插法创建链表/n");   for(i=0;i<10;i++){    createdlinklisthead(head,tail,i);  }  traverselist(head,tail);  for(i=0;i<10;i++){    printf("表中值为%d的元素的位置为",i);     printf("%d位/n",locateelem(head,tail,i));  }  printf("表长为%d/n",listlength(head,tail));  printf("逆序打印链表");  inverse(head,tail);  for(i=0;i<10;i++){    deleteelem(head,tail,1,&data);    printf("被删除的元素为%d/n",data);  }  traverselist(head,tail);  if(emptylinklist(head,tail))    printf("链表为空/n");  else    printf("链表不为空/n");    printf("尾插法创建链表/n");  for(i=0;i<10;i++){    //inserttail(head,tail,i);    createdlinklisttail(head,tail,i);  }  traverselist(head,tail);  printf("逆序打印链表");  inverse(head,tail);}