仅供参考：
//不带表头结点的循环双向链表
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <time.h>
#include <locale.h>
struct NODE {
int data;
struct NODE *next;
struct NODE *prev;
} *head,*p,*q,*s,*p1,*p2,*q1,**ta;
int i,k,n,t,m,v,N=10;
int main() {
setlocale(LC_ALL,"chs");
srand(time(NULL));
head=NULL;
printf("创建%d个节点的循环双向链表:",N);//创建N个节点的循环双向链表
p=head;
for (i=0;i<N;i++) {
q=(struct NODE *)malloc(sizeof(struct NODE));
if (NULL==q) exit(1);
q->data=rand()%100;//填写0..99的随机值
q->next=NULL;
q->prev=NULL;
if (NULL==p) {
head=q;
p=head;
} else {
p->next=q;
q->prev=p;
p=q;
}
}
p->next=head;
head->prev=p;
//输出整个循环双向链表
s=head;
while (1) {
if (NULL==s) {
printf("\n");
break;
}
printf("%02d(=)",s->data);
if (NULL!=s->next && s->next->prev!=s) {printf(" !\n");break;}
s=s->next;
if (s==head) {
printf(" Loop\n");
break;
}
}
k=3;
v=5;
printf("将值为%d的结点插入到循环双向链表的第%d个结点前:",v,k);//将值为v的结点插入到循环双向链表的第k个结点前
n=0;
p=head;
while (1) {
if (NULL==p) {
break;
}
n++;
if (k==1) {
q=(struct NODE *)malloc(sizeof(struct NODE));
if (NULL==q) exit(1);
q->data=v;
q->next=head;
q->prev=head->prev;
head->prev->next=q;
head->prev=q;
head=q;
break;
} else {
if (k-1==n) {
q=(struct NODE *)malloc(sizeof(struct NODE));
if (NULL==q) exit(1);
q->data=v;
q->next=p->next;
q->prev=p;
p->next->prev=q;
p->next=q;
break;
}
}
p=p->next;
if (p==head) break;
}
//输出整个循环双向链表
s=head;
while (1) {
if (NULL==s) {
printf("\n");
break;
}
printf("%02d(=)",s->data);
if (NULL!=s->next && s->next->prev!=s) {printf(" !\n");break;}
s=s->next;
if (s==head) {
printf(" Loop\n");
break;
}
}
k=5;
printf("删除第%d个节点:",k);//删除第k个节点
n=0;
p=head;
while (1) {
if (NULL==p) {
break;
}
n++;
if (k==1) {
q=head;
head=head->next;
head->prev=q->prev;
q->prev->next=head;
if (q==head) head=NULL;
free(q);
break;
} else {
if (k-1==n) {
q=p->next;
p->next=q->next;
q->next->prev=p;
free(q);
break;
}
}
p=p->next;
if (p==head) break;
}
//输出整个循环双向链表
s=head;
while (1) {
if (NULL==s) {
printf("\n");
break;
}
printf("%02d(=)",s->data);
if (NULL!=s->next && s->next->prev!=s) {printf(" !\n");break;}
s=s->next;
if (s==head) {
printf(" Loop\n");
break;
}
}
printf("从小到大排序:");//从小到大排序
for (p=head;p!=NULL;) {
p1=p->prev;
for (q=p->next,q1=p;q!=NULL;) {
if (p->data > q->data) {
//交换data
// printf("swap %02d %02d\n",p->data,q->data);
// t=p->data;p->data=q->data;q->data=t;
//或者
//交换prev和next
// printf("swap %02d %02d\n",p->data,q->data);
if (p==head) {//p是头
if (p->next==q) {//pq挨着
head=q;
head->prev=p1;
p1->next=q;
p->next=q->next;
p->prev=q;
q->next->prev=p;
q->next=p;
q=p;
p=head;
} else {//pq不挨着
head=q;
head->prev=p1;
p1->next=q;
p2=p->next;
p->next=q->next;
p->next->prev=p;
p->prev=q1;
q->next->prev=p;
q->next=p2;
p2->prev=q;
q1->next=p;
q=p;
p=head;
}
} else {//p不是头
if (p->next==q) {//pq挨着
p1->next=q;
p->next=q->next;
p->prev=q;
q->next->prev=p;
q->next=p;
q->prev=p1;
q=p;
p=p1->next;
} else {//pq不挨着
p1->next=q;
p2=p->next;
p->next=q->next;
p->prev=q->prev;
q->next->prev=p;
q->next=p2;
q->prev=p1;
p2->prev=q;
q1->next=p;
q=p;
p=p1->next;
}
}
//输出整个循环双向链表
// s=head;
// while (1) {
// if (NULL==s) {
// printf("\n");
// break;
// }
// printf("%02d(=)",s->data);
// if (NULL!=s->next && s->next->prev!=s) {printf(" !\n");break;}
// s=s->next;
// if (s==head) {
// printf(" Loop\n");
// break;
// }
// }
// printf("head,p,q:%02d %02d %02d\n",head->data,p->data,q->data);
// getchar();
}
q1=q;q=q->next;
if (q==head) break;
}
p=p->next;
if (p->next==head) break;
}
//输出整个循环双向链表并计算链表长度n
n=0;
s=head;
while (1) {
if (NULL==s) {
printf("\n");
break;
}
printf("%02d(=)",s->data);
if (NULL!=s->next && s->next->prev!=s) {printf(" !\n");break;}
n++;
s=s->next;
if (s==head) {
printf(" Loop\n");
break;
}
}
printf("将整个链表逆序:");//将整个链表逆序
if (n>=2) {
p=head;
while (1) {
q=p->prev;p->prev=p->next;p->next=q;
p=p->next;
if (p==head) break;
}
}
//输出整个循环双向链表
s=head;
while (1) {
if (NULL==s) {
printf("\n");
break;
}
printf("%02d(=)",s->data);
if (NULL!=s->next && s->next->prev!=s) {printf(" !\n");break;}
s=s->next;
if (s==head) {
printf(" Loop\n");
break;
}
}
m=4;
n=6;
printf("将循环双向链表中前%d个结点和后%d个结点进行互换:",m,n);//将循环双向链表中前m个结点和后n个结点进行互换,m+n为链表总长
k=0;
p=head;
while (1) {
if (NULL==p) {
break;
}
k++;
if (m==k) {
q=p;
break;
}
p=p->next;
if (p==head) break;
}
head=q->next;
//输出整个循环双向链表
s=head;
while (1) {
if (NULL==s) {
printf("\n");
break;
}
printf("%02d(=)",s->data);
if (NULL!=s->next && s->next->prev!=s) {printf(" !\n");break;}
s=s->next;
if (s==head) {
printf(" Loop\n");
break;
}
}
//释放所有节点
p=head;
while (1) {
if (NULL==p) {
break;
}
q=p->next;
free(p);
p=q;
if (p==head) {
break;
}
}
return 0;
}
//创建10个节点的循环双向链表:12(=)46(=)31(=)63(=)25(=)91(=)39(=)02(=)92(=)68(=) Loop
//将值为5的结点插入到循环双向链表的第3个结点前:12(=)46(=)05(=)31(=)63(=)25(=)91(=)39(=)02(=)92(=)68(=) Loop
//删除第5个节点:12(=)46(=)05(=)31(=)25(=)91(=)39(=)02(=)92(=)68(=) Loop
//从小到大排序:02(=)05(=)12(=)25(=)31(=)39(=)46(=)68(=)91(=)92(=) Loop
//将整个链表逆序:92(=)91(=)68(=)46(=)39(=)31(=)25(=)12(=)05(=)02(=) Loop
//将循环双向链表中前4个结点和后6个结点进行互换:39(=)31(=)25(=)12(=)05(=)02(=)92(=)91(=)68(=)46(=) Loop
//
