单链表转成双向循环链表

#include<stdio.h>
#include<stdlib.h>
struct node
{
 int data;
 struct node*next; 
};
struct Binode
{
 int data;
 struct Binode*next;
 struct Binode*prev;
};
struct Binode*func(struct node*head);
int main()
{
 //新建衣蛾单链表
 struct node*head=NULL;
 struct node*temp;
 struct node*newnode;
 struct Binode*Bihead=NULL;
 struct Binode*p;
 int i;
 head=(struct node*)malloc(sizeof(struct node));
 head->data=0;
 temp=head;
 for(i=1;i<=9;i++)
 {
  newnode=(struct node*)malloc(sizeof(struct node));
  newnode->data=i;
  temp->next=newnode;
  temp=newnode;
 }
 temp->next=NULL;
 
 //打印单链表
 temp=head;
 while(temp)
 {
  printf("%d\n",temp->data);
  temp=temp->next;
 }
 
 //单链表转成双向循环链表
  Bihead=func(head);
  if(Bihead==NULL) printf("error\n");
  printf("%d\n",Bihead->data);
  p=Bihead->next;
  while(p!=Bihead)
  {
   printf("%d\n",p->data);
   p=p->next;
  } 
 
}
struct Binode*func(struct node*head)
{
 struct Binode*front,*rear,*newnode;
 if(head==NULL) return NULL;
 front=(struct Binode*)malloc(sizeof(struct Binode));
 front->data=head->data;
// printf("%d\n",front->data);
 rear=front;
 while(head->next)
 {
  newnode=(struct Binode*)malloc(sizeof(struct Binode));
  newnode->data=head->next->data;
 // printf("%d\n",newnode->data);
  rear->next=newnode;
  newnode->prev=rear;
  rear=newnode;
  head=head->next;
 }
 front->prev=rear;
 rear->next=front;
 return front;
  
}