判断单循环链表中是否存在环

#include<stdio.h>
#include<stdlib.h>

typedef struct Node{
	int data;
	struct Node* next;
}Node;
typedef struct Node* LinkList;

void InitialLinkList(LinkList *L){
	(*L) = (LinkList)malloc(sizeof(struct Node));
	if(!(*L)){
		printf("Error:InitialLinkList:malloc\n");
		exit(1);
	}
	(*L)->next = NULL;
}
void CreateSimpleCycleList_withoutLoop(LinkList *L,int number){
	int count;
	LinkList new,tail = (*L);
	printf("Create SimpleCycleList_withoutLoop\n");
	for(count = 1;count <= number; count++){
		new = (LinkList)malloc(sizeof(struct Node));
		if(!(new)){
			printf("Error:CreateSimpleCycleList_withoutLoop\n");
			exit(1);
		}
		printf("please enter %d element:  ",count);
		scanf("%d",&(new->data));
		new->next = tail->next;
		tail->next = new;
		tail = new;
	}
}
void CreateSimpleCycleList_withLoop(LinkList *L,int number,int loopInIndex){
/* 第一个参数LinkList是要创建的有环的链表
 * 第二个参数number是链表的长度
 * 第三个参数loopInIndex是指示环由链表的末尾指向了第几个元素，0则表示是指向了头结点。
 * */
	int count;
	LinkList new,temp = *L,temp1 = *L;
	if(loopInIndex > number){
		printf("Error:CreateSimpleCycleList_withLoop:loopInIndex\n");
	}
	else{
		printf("Create SimpleCycleList_withLoop\n");
		for(count = 1; count <= number; count++){
			new = (LinkList)malloc(sizeof(struct Node));
			if(!new){
				printf("Error:CreateSimpleCycleList_withLoop\n");
				exit(1);
			}
			printf("please enter %d element  ",count);
			scanf("%d",&(new->data));
			temp->next = new;
			new->next = *L;
			temp = new;
		}
		for(count = 0;count < loopInIndex; count++){
			temp1 = temp1->next;
		}
		temp->next = temp1;
	}
}
void JodgeLoop(LinkList L){
	LinkList p = L,q = L;
	int step_o = 0,step_i = 0;
	int isLoop = 0;
	while(p){
		step_i = 0;
		q = L;
		while(q != p){
			q = q->next;
			step_i++;
		}
		if(step_o != step_i){
			isLoop = 1;
			break;
		}
		p = p->next;
		step_o++;
	}
	if(isLoop == 1)
		printf("Exist loop in this List.Appear in position %d\n",step_i);
	else
		printf("Dose no Exist loop in this List!\n");
}
void JodgeLoop_2(LinkList L){
	LinkList quick = L,slow = L;
	int isLoop = 0;
	while(quick != NULL && quick->next != NULL){
		quick = quick->next->next;
		slow = slow->next;	
		if(quick == slow){
			isLoop = 1;
			break;
		}
	}
	if(isLoop)
		printf("Exist loop in this List.\n");
	else
		printf("Dose no Exist loop in this List!\n");
}
void Display_withoutLoop(LinkList L){
	while(L->next != NULL){
		L = L->next;
		printf("%d ",L->data);
	}
	printf("\n");
}

int main(){
	LinkList L1;
	LinkList L2;
	InitialLinkList(&L1);
	InitialLinkList(&L2);
	CreateSimpleCycleList_withLoop(&L1,5,1);
	CreateSimpleCycleList_withoutLoop(&L2,4);
	JodgeLoop(L1);
	JodgeLoop(L2);
	JodgeLoop_2(L1);
	JodgeLoop_2(L2);
	return 0;

}