链表实现约瑟夫环

#include<stdio.h>
#include<malloc.h>

#define false 0;
#define ok 1;

typedef struct node
{
	int data;
	int num;
	struct node * next;
} node, *linklist;

//初始化链表
void initlist(linklist * l)
{
	* l = (linklist)malloc(sizeof(node));
	(*l)->next = *l;
}

//用尾插法建立新链表
void greatefromtail(linklist l, int n)
{
	node * s, * r;
	int flag = 1;
	int data, num;
	int j = 0;
	r = l;
	while(flag)
	{
		if(j < n)
		{
			printf("请输入第%d位密码\n", j+1);
			scanf("%d", &data);
			s = (node *)malloc(sizeof(node));
			s->data = data;
			s->num = j+1;
			r->next = s;
			r = s;
			j++;
		}
		else
		{
			flag = 0;
			r->next = l->next;
		} 
	}
}

//删除链表l中第i个元素
linklist dellist(linklist l, int * a)
{
	node * pre, * r, *s;
	int j = 1;
	pre = l;
	if(*a == 1)
	{
		s = pre;
		while(s->next != pre)
		{
			s = s->next;
		}
		*a = pre->data;
		s->next = pre->next;
		return pre;
	}
	else
	{
		while(j < *a-1)
		{
			pre = pre->next;
			j++;
		}
		r = pre->next;
		*a = r->data; 
		pre->next = r->next;
		return r;
	}
}

int main(void)
{
	int n,m; //总人数n,初始报人数及后续密码存放m
	int i = 0,j = 0;
	linklist l, q;  //原链表头指针
	node * r; //删除的的节点存放r,建立输出链表中间变量s
	
	printf("请输入总人数n\n");
	scanf("%d", &n);
	printf("请输入初始报数人数m\n");
	scanf("%d", &m);

	initlist(&l); //初始化原链表
	greatefromtail(l, n); //尾插法建立链表
	q = l->next;

	for(i = 0; i < n; i++)
	{
		r = dellist(q, &m);
		printf("%2d", r->num);
		q = r ->next;
	}
	return 0;
}