双向链表基本操作

双向链表
输入一个双向链表，显示些双向链表并对此双向链表排序运行结果：
源程序：
#include<iostream.h>
#include<stdlib.h>
#include <stdio.h>
typedef struct Link/*双向链表结构体*/
{
int data;
struct Link *lift;
struct Link *right;
}linkx,*linky;
linky Init();/*建立双向链表*/
void PrLink(linky p);/*输出双向链表*/
linky Sort(linky head);/*对双向链表排序*/
linky Swap(linky head,linky one,linky two);/*任意交换双向链表两个结点的地址*/ void main(void)
{
linky head;
head=Init();
head=Sort(head);
PrLink(head);
}
linky (Init())/*建立链表*/
{
linky p,q,head;
int n=0;
head=p=q=(linky)malloc(sizeof(linkx));
printf("排序前的链表: ");
scanf("%d",&p->data);/*输入数据*/
head->lift=NULL;
n++;
while(n!=10)/*一直输入到规定的数字个数停止*/
{
q=p;
p=(linky)malloc(sizeof(linkx));
scanf("%d",&p->data);/*输入数据*/
q->right=p;
p->lift=q;
n++;
}
p->right=NULL;
return(head);
}
linky Swap(linky head,linky one,linky two)/*任意交换两个结点*/ {linky temp;
if(one->lift==NULL&&two->right==NULL)/*首和尾巴的交换*/ {
if(one->right==two)/*只有两个结点的情况下*/
{
two->right=one;
two->lift=NULL;
one->lift=two;
one->right=NULL;
head=two;
}
else/*有间隔的首尾交换*/
{
one->right->lift=two;
two->lift->right=one;
two->right=one->right;
one->lift=two->lift;
two->lift=one->right=NULL;
head=two;/*尾结点成为头结点*/
}
}
else if(two->right==NULL)/*尾和任意一个交换*/ {
if(one->right==two)/*交换最后两个结点*/ {
one->lift->right=two;
two->lift=one->lift;
two->right=one;
one->lift=two;
one->right=NULL;
}
else/*和前面其他结点交换*/
{
temp=two->lift;
temp->right=one;
one->lift->right=two;
one->right->lift=two;
two->lift=one->lift;
two->right=one->right;
one->lift=temp;
one->right=NULL;
}
}
else if(one->lift==NULL)/*头和任意一个交换*/ {
if(one->right==two)/*交换头两个结点*/
{
two->right->lift=one;
one->right=two->right;
one->lift=two;
two->right=one;
two->lift=NULL;
head=two;
}
else/*头结点和后面其他结点交换*/
{
temp=one->right;
temp->lift=two;
one->lift=two->lift;
one->right=two->right;
two->lift->right=one;
two->right->lift=one;
two->right=temp;
two->lift=NULL;
head=two;/*交换的结点成为头结点*/
}
}
else/*当中的任意两个交换*/
{
if(one->right==two)/*交换连在一起的两个结点*/ {
temp=one->lift;
one->lift->right=two;
one->right->lift=two;
one->lift=two;
one->right=two->right;
two->right->lift=one;
two->right=one;
two->lift=temp;
}
else/*交换隔开的两个结点*/
{
one->lift->right=two;
one->right->lift=two;
one->lift=two->lift;
temp=one->right;
one->right=two->right;
two->lift->right=one;
two->right->lift=one;
two->right=temp;
two->lift=one->lift;
}
}
return(head);
}
linky Sort(linky head)/*对链表排序*/
{
linky i,j,t,p;
int max;
p=head;
for(i=p;i->right!=NULL;i=i->right)/*用选择法的思想对这些结点排序*/ {
max=i->data;
for(j=i->right;j!=NULL;j=j->right)
if(j->data<max)
{
max=j->data;
t=j;
}
if(max!=i->data)/*假如没有找到比i小的结点*/
{
head=Swap(head,i,t);/*因为最终返回的是头结点,而头结点又有可能变化,所以每次头结点返回*/
i=t;
}
}
return(head);
}
void PrLink(linky p)/*输出链表*/
{
linky q;
printf("排序后: ");
do
{
q=p;
printf("%d ",p->data);
p=p->right;
free(q);/*释放输出结点*/
}
while(p!=NULL);
}。