POJ2080:Calendar(计算日期)

#include <iostream>
using namespace std;
int mds[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
char Week[8][20]={"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"};
bool isLeap(int year)
{
    if((year%4==0&&year%100!=0)||year%400==0)
    {
        return true;
    }
    return false;
}
int main()
{
    int standard=0;
    for(int i=2000;i<=2015;i++)    
    {
        if(isLeap(i))    standard+=366;
        else    standard+=365;    
    }
    for(int i=1;i<=6;i++)
    {
        standard+=mds[i];
    }
    if(isLeap(2016))    standard++;
    standard+=3;//2016-07-03 is Sunday.
    int diff;
    int days;
    while(cin>>days&&days!=-1)
    {
        diff=days-standard;
        diff++;
        int year=2000;
        int d=1;
        int m=1;
        while(true)
        {
            if(isLeap(year))
            {
                if(days>=366)
                {
                    days-=366;
                    year++;
                }
                else    break;
            }    
            else
            {
                if(days>=365)
                {
                    days-=365;
                    year++;
                }
                else    break;
            }
        }
        while(true)
        {
            int ms=mds[m];
            if(isLeap(year)&&m==2)
            {
                ms++;
            }
            if(days>=ms)
            {
                days-=ms;
                m++;
            }
            else    break;
        }
        d+=days;
        cout<<year<<"-";
        if(m<10)    cout<<"0";
        cout<<m<<"-";
        if(d<10)    cout<<"0";
        cout<<d<<" ";
        
        if(diff>=0)
        {
            diff%=7;
            cout<<Week[diff]<<endl;
        }
        else
        {
            diff=-diff;
            diff%=7;
            if(diff==0)    diff=7;
            cout<<Week[7-diff]<<endl;
        }
    }
    return 0;
}