POJ 2080 Calendar

 1 #include<stdio.h>
 2 int rm[]={31,29,31,30,31,30,31,31,30,31,30,31};  
 3 int pm[]={31,28,31,30,31,30,31,31,30,31,30,31};  
 4 int isp(int year)
 5 {
 6     if((year%4==0&&year%100!=0)||year%400==0) return 1;   
 7     
 8     return 0; 
 9 }
10 int main()
11 {
12     
13     int y,m,n,d,dd,day;
14     while(scanf("%d",&n)!=EOF)
15     {
16         if(n==-1)break;
17         y=2000,m=0,day=n;
18         while(n>=(isp(y)?366:365))
19         {
20             n=n-(isp(y)?366:365);
21             y++;
22         }
23         while(n>=(isp(y)?rm[m]:pm[m]))
24         {
25             n=n-(isp(y)?rm[m]:pm[m]);
26             m=(m+1)%12;
27         }
28         d=n%(isp(y)?rm[m]:pm[m])+1;
29         m=m+1;
30         printf("%d",y);
31         m<10?printf("-0%d",m):printf("-%d",m);
32         d<10?printf("-0%d",d):printf("-%d",d);
33         dd=day%7;
34         switch(dd)
35         {
36         case 0 : printf(" Saturday\n");break;
37         case 1 : printf(" Sunday\n");break;
38         case 2 : printf(" Monday\n");break;
39         case 3 : printf(" Tuesday\n");break;
40         case 4 : printf(" Wednesday\n");break;
41         case 5 : printf(" Thursday\n");break;
42         case 6 : printf(" Friday\n");break;
43         }
44         
45         
46     }
47     return 0;
48 }