POJ 2080(calender)

//以后遇到闰年的问题，坚决用二维数组 
#include<stdio.h>
#include<string.h>
#define N 10010
char date[7][10]={"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"};
int vis[2][12]={31,28,31,30,31,30,31,31,30,31,30,31,31,29,31,30,31,30,31,31,30,31,30,31}; //vis[0]表示非闰
int leap[N];
void isleap()
{
    int i,j;
    memset(leap,0,sizeof(leap));
    for(i=2000;i<N;i++)
    if(i%4==0&&i%100!=0||i%400==0)
        leap[i]=1;
}
int main()
{
    int i,j,k;
    int num;
    int flag;//星期代表元 
    int year;
    isleap();
    while(scanf("%d",&num),num!=-1)
    {
        k=num;
        flag=(num+6)%7;//第一天星期6，先求flag是因为，后来num要改变 
        for(i=2000;num>=(leap[i]==1?366:365);i++)//第一次判断便不成立时，i没有自增，以后就自增了 
        {
            if(leap[i])
                num-=366;
            else
                num-=365;
        }
       // printf("i=%d\n",i);
        for(j=0;num>=vis[leap[i]][j]&&j<12;j++)//月份
        {
            num-=vis[leap[i]][j];
        }
        printf("%d-%02d-%02d %s\n",i,j+1,num+1,date[flag]);//注意6要输出为06 
    }
    return 0;
}