算法导论10.2-5循环链表实现

循环链表插入，删除和查找的初步实现，但是感觉写的漏洞非常多，再研究研究


#include<iostream>
using namespace std;
struct my_list
{
	my_list *pre,*next;
	int key;
};
my_list* Init_list()
{
	my_list *list = new my_list();
	if(list == NULL)
		cout << "申请内存空间失败\n";
	list->pre = list->next = list;
	return list;
}
my_list* Create_list()
{
	my_list *list1 = new my_list();
	int value = 0;
	my_list *list = list1;
	cout << "请输入各元素值：\n";
	while(cin >> value)
	{
		my_list *temp = new my_list();
		temp->key = value;
		list->next = temp;
		temp->pre = list;
		list = temp;
	}
	list->next = list1;
	list1->pre = list;
	return list1;
}
bool list_empty(my_list *list)
{
	if(list->next == list && list->pre == list)
		return true;
	return false;
}
void list_insert(my_list *list, int i, int value)
{
   my_list *temp = list->next;
   while(--i)
   {
	   temp = temp->next;
	   if(temp == list)
	   {
		   cerr << "插入位置错误\n";
		   exit(1);
	   }
   }
   my_list *p = new my_list();
   p->key = value;
   p->next = temp->next;
   temp->next->pre = p;
   temp->next = p;
   p->pre = temp;
}

void list_delete(my_list *list, int i)
{
   my_list *temp = list->next;
   while(i--)
   {
	   temp = temp->next;
	   if(temp == NULL || temp == list)
	   {
		   cerr << "插入位置错误\n";
		   exit(1);
	   }
   }
   my_list *temp1 = temp;
   temp1->pre->next = temp1->next;
   temp->next->pre = temp1->pre;
   free(temp1);
}

int list_search(my_list *list,int key)
{
	my_list *temp = list->next;
	int i = 0;
	while(temp != list)
	{
		if(temp ->key == key)
			return i;
		temp = temp->next;
		++i;
	}
	return -1;
}
void print(my_list *list)
{
	my_list *temp = list->next;
	cout << "链表的元素是：\n";
	while(temp != list)
	{
		cout << temp->key << " ";
		temp = temp->next;
	}
	cout << endl;
}
int main()
{
	my_list *list = Init_list();
	list = Create_list();
	print(list);
	list_insert(list,2,10);
	print(list);
	list_delete(list,3);
	print(list);
	cout << list_search(list, 1) << endl;
}