# include <stdio.h>
# include <stdlib.h>
typedef struct node //定義鏈表中結點的結構
{
 int code; 
 struct node *next;
}NODE,*LinkList; 

/*錯誤信息輸出函數*/
void Error(char *message)
{
 fprintf(stderr,"Error:%s/n",message);
 exit(1);
}

//創建循環鏈表
LinkList createList(int n)
{
 LinkList head; //頭結點
 LinkList p; //當前創建的節點
 LinkList tail; //尾節點
 int i;
 head=(NODE *)malloc(sizeof(NODE));//創建循環鏈表的頭節點
 if(!head)
 {
 Error("memory allocation error!/n");
 }
 head->code=1;
 head->next=head;
 tail=head;
 for(i=2;i<n;i++)
 {
 //創建循環鏈表的節點
 p=(NODE *)malloc(sizeof(NODE));
 tail->next=p;
 p->code=i;
 p->next=head;
 tail=p;
 }
 return head;
}

//創建循環鏈表方法2(軟件設計師教程書上的方法)
LinkList createList2(int n)
{
 LinkList head,p;
 int i;
 head=(NODE *)malloc(sizeof(NODE));
 if(!head)
 {
 printf("memory allocation error/n");
 exit(1);
 }
 head->code=1;
 head->next=head;
 for(i=n;i>1;--i)
 {
 p=(NODE *)malloc(sizeof(NODE));
 if(!p)
 {
  printf("memory allocation error!/n");
  exit(1);
 }
 p->code=i;
 p->next=head->next;
 head->next=p;
 }
 return head;
}

void output(LinkList head)
{
 LinkList p;
 p=head;
 do
 {
 printf("%4d",p->code);
 p=p->next;
 }
 while(p!=head);
 printf("/n");
}

void main(void)
{
 LinkList head;
 int n;
 printf("input a number:");
 scanf("%d",&n);
 head=createList(n);
 output(head);
}