C语言题目4

//用C语言编写程序：建立一个顺序排列环状链表，有一个header指针指向最小节点（整数5）。
//输入一个整数，如果该整数在链表中存在，则删除该节点，并且header指针仍然指向最小的节点；
//若不存在，则不作任何操作，最后输出链表中的所有数据。
#include "stdio.h"
#include "stdlib.h"

typedef struct node{
  int x;
  struct node *next;
}llnode;

void showList(llnode* head)
{
  llnode* p=head;
  int i = 0;
  printf("一共有%d个元素，链表中的数据如下：",head->x);
  p = head->next;
  while(i < 3*(head->x))
    {
      printf("%d ",p->x);
      p = p->next;
      i = i+1;
      if(i%(head->x)==0)
	{
	  printf("---loop--- ");
	}
    }
  printf("...\n");
}

int main()
{
  int number=0;
  llnode* head = (llnode *)malloc(sizeof(llnode));
  llnode* p=head;
  llnode* q=head;
  llnode* start=head;
  char buffer;
  int find=0;
  head->x = 0;//用来存储数据节点个数
  head->next = NULL;
  printf("请输入初始化链表的整数，数字之间用空格隔开，以输入#并回车结束：");
  while(scanf("%d",&number))
    {
      llnode *n = (llnode *)malloc(sizeof(llnode));
      n->x = number;
      n->next = NULL;
      //如果没有数据节点
      if(head->next == NULL)
	{
	  head->next = n;
	  head->x ++;
	  n->next = n;
	}
      //如果用修改head指向
      else if((n->x) < (head->next->x))
	{
	  p = head->next;
	  if(p->next == p)//只有一个数据节点
	    {
	      p->next = n;
	      head->next = n;
	      n->next = p;
	    }
	  else
	    {
	      p = p->next;
	      while(p->next != head->next)
		{
		  p = p->next;
		}
	      n->next = head->next;
	      p->next = n;
	      head->next = n;
	    }
	  head->x ++;
	}
      //如果不用修改head指向
      else
	{
	  find = 0;
	  p = head->next->next;
	  q = head->next;
	  start = q;
	  while(1)
	    {
	      if((n->x)>(p->x))
		{
		  p = p->next;
		  q = q->next;
		}
	      else
		{
		  q->next = n;
		  n->next = p;
		  head->x ++;
		  break;
		}
	      if(q->next == start)
		{
		  n->next = p;
		  q->next = n;
		  head->x ++;
		  break;
		}
	    }
	}
    }
  showList(head);
  while((buffer = getchar())!='\n' && buffer!=EOF);//具备可移植性的清空缓冲区方法
  printf("顺序循环链表已经建立，请输入要删除的整数，输入#并回车退出程序:");
  while(scanf("%d", &number))
    {
      p = head->next;
      //用修改head指向
      if(p->x == number)
	{
	  if(p->next == p)
	    {
	      free(p);
	      head->next = NULL;
	    }
	  else
	    {
	      p = p->next;
	      while(p->next != head->next)
		{
		  p = p->next;
		}
	      q = head->next;
	      p->next = q->next;
	      head->next = q->next;
	      free(q);
	    }
	  head->x --;
	}
      //后续数据节点
      else
	{
	  q = p;
	  start = q;
	  p = p->next;
	  while(1)
	    {
	      if(p->x != number)
		{
		  p = p->next;
		  q = q->next;
		}
	      else
		{
		  q->next = p->next;
		  free(p);
		  head->x --;
		  break;
		}
	      if(p == start)
		{
		  break;
		}
	    }
	}
      showList(head);
      while((buffer = getchar())!='\n' && buffer!=EOF);//具备可移植性的清空缓冲区方法
      printf("顺序循环链表已经建立，请输入要删除的整数，输入#并回车退出程序:");
    }
  return 1;
}