双向链表

#include<stdio.h>
#include<malloc.h>

#define ERROR 0
#define OK 1
#define EQUAL 1
#define OVERFLOW -1
#define LIST_INIT_SIZE 100
#define LISTINCREMENT 10

struct STU{
  char name[20];
  char stuno[10];
  int age;
  int score;
}stu[50];
typedef struct STU ElemType;

struct LNODE
{
  ElemType data;
  struct LNODE *prior;
  struct LNODE *next;
};

typedef struct LNODE LNode;
typedef struct LNODE *LinkList;

/*初始化链表L*/
int init(LinkList *L)
{
  *L=(LNode *)malloc(sizeof(LNode));
  if(!L)   exit(ERROR);
  (*L)->next=NULL;
  (*L)->prior=NULL;
  return OK;
}/*init */

/*返回链表长度*/
int ListLength(LinkList L)
{
  int j=0;
  while (L->next)
    {
      L=L->next;
      j++;
    }
  return j;
}

/*获得链表L的第i个元素,并赋值给指针e*/
int GetElem(LinkList L,int i,ElemType *e)
{
  LinkList p; int j;
  p=L->next;j=1;
  while(p&&j<i){
    p=p->next;++j;
  }
  if(!p||j>1)  return ERROR;
  *e=p->data;
  return OK;
}

/*判断e1与e2两元素是否相等*/
int EqualList(ElemType *e1,ElemType *e2)
{
  if (strcmp(e1->name,e2->name)==0)
    return 1;
  else
    return 0;
}

/*比较元素e1与e2*/
int Less_EqualList(ElemType *e1,ElemType *e2)
{
  if (strcmp(e1->name,e2->name)<=0)
    return 1;
  else
    return 0;
}

/*从线性链表L中删除第i个元素*/
int DeleteElem(LinkList L,int i)
{
    LinkList p;  int j;
    j=0;
    p=L;
    while (p->next && j<i){
      p=p->next; ++j;
    }
    if(!p)  return ERROR;
    p->prior->next=p->next;
    p->next->prior=p->prior;
    free(p);
    return OK;
} 

/*元素e是否在链表La中*/
int LocateElem(LinkList La,ElemType e,int type)
{
  int i;
  LinkList p;
  p=La;
  switch (type)
    {
      case EQUAL:
   while(p->next)
     {
       p=p->next;
       if(EqualList(&p->data,&e))
        return 1;
     }
   return 0;
 break;
      default:
 break;
    }
  return 0;
}

void MergeList(LinkList La,LinkList Lb,LinkList *Lc)
{
  LinkList pa,pb,pc;
  pa=La->next;pb=Lb->next;
  *Lc=pc=La;
  while(pa && pb)
    {
      if(Less_EqualList(&pa->data,&pb->data))
 {
   pc->next=pa;pa->prior=pc;pc=pa;pa=pa->next;
 }
      else
 {
   pc->next=pb;pb->prior=pc;pc=pb;pb=pb->next;
 }
    }
  pc->next=pa?pa:pb;
  free(Lb);
}

int printlist(LinkList L)
{
  int i;
  LinkList p;
  p=L;
  printf("name       stuno        age     score\n");
  while(p->next)
    {
      p=p->next;
      printf("%-10s %s\t%d\t%d\n",  p->data.name,  p->data.stuno,
   p->data.age,  p->data.score);
    }
  printf("\n");
}

int ListInsert(LinkList L,int i,ElemType e)
{
  LinkList p,s;
  int j;
  p=L;j=0;
  while(p&&j<i-1)
    {
      p=p->next;
      ++j;
    }
  if(!p||j>i-1) return ERROR;
  s=(LinkList)malloc(sizeof(LNode));
  s->data=e;
  s->next=p->next;
  s->prior=p;
  p->next=s;
  return OK;
}/*ListInsert Before i */

int main()
{
  struct STU e,t,*p;
  LinkList La,Lb,Lc;

  printf("\n\n-------------------List Demo is running...----------------\n\n");
  printf("First is InsertList function.\n");
  init(&La);

  strcpy(e.name,"stu1");
  strcpy(e.stuno,"100001");
  e.age=80;
  e.score=1000;
  ListInsert(La,1,e);
  strcpy(e.name,"stu3");
  strcpy(e.stuno,"100002");
  e.age=80;
  e.score=1000;
  ListInsert(La,2,e);

  printlist(La);
  getch();

  strcpy(e.name,"stu5");
  strcpy(e.stuno,"100003");
  e.age=80;
  e.score=1000;
  ListInsert(La,3,e);
 
  printlist(La);
  getch();
 
  printf("Test DeleteElem\n");
  DeleteElem(La,1);
  printlist(La);
  getch();

  init(&Lb);

  strcpy(e.name,"stu2");
  strcpy(e.stuno,"100001");
  e.age=80;
  e.score=1000;
  ListInsert(Lb,1,e);
  strcpy(e.name,"stu4");
  strcpy(e.stuno,"100002");
  e.age=80;
  e.score=1000;
  ListInsert(Lb,2,e);

  strcpy(e.name,"stu6");
  strcpy(e.stuno,"100001");
  e.age=80;
  e.score=1000;
  ListInsert(Lb,3,e);

  printlist(Lb);
  getch();

  MergeList(La,Lb,&Lc);
  printlist(Lc);
  getch();

  printf("\n\n\n\n\n\nWelcome to visit http://zmofun.heha.net !\n\n\n\n\n\n\n");
  getch();
  return 0;
}