POJ

 1 #include<stdio.h>
 2 int type(int);   /*判断是否为闰年*/
 3 char week[7][10]={"Saturday","Sunday","Monday","Tuesday","Wednesday","Thursday","Friday"};
 4 int year[2]={365,366};   /*year[0]表示非闰年的天数，year[1]表示闰年的天数。*/
 5 int month[2][12]={31,28,31,30,31,30,31,31,30,31,30,31,
 6                   31,29,31,30,31,30,31,31,30,31,30,31};
 7 /*month[0]表示非闰年里每个月的天数，month[1]表示闰年里每个月的天数。*/
 8 int main()
 9 {    int days,dayofweek;  /*days表示输入的天数，dayofweek表示星期几。*/
10     int i,j;
11     while(scanf("%d",&days)&&days!=-1)
12     {    dayofweek=days%7;
13         for(i=2000;days>=year[type(i)];i++)
14             days-=year[type(i)];
15         for(j=0;days>=month[type(i)][j];j++)
16             days-=month[type(i)][j];
17         printf("%d-%02d-%02d %s\n",i,j+1,days+1,week[dayofweek]);
18     }
19     return 0;
20 }
21 int type(int m)
22 {    if(m%4!=0||(m%100==0&&m%400!=0))
23         return 0;
24     else return 1;
25 }