各位大侠帮我看看哪儿出问题了，第二次输入就报错（写入位置发生访问冲突）

//天数转换为周数和天数，利用while循环重复输入
#include <stdio.h>
int main (void)
{
   int week,day,day2;
   printf ("请输入天数：");
   scanf ("%d",&day);
   while (day>0)
   {
       week = day/7;
       day2 = day&7;

       printf ("%d days 等于 %d周%d days\n",day,week,day2);
       printf ("请输入下一个值：");
       scanf ("%d",day);
   }
   printf ("done");
   system ("pause");
   return 0;
}

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