一个简单的时间和日期程序

#include <iostream>
using namespace std;

struct Date{
int y;  // year
int m;  //month
int d;  //day
};

bool is_leap(int y)
{
return (y%4==0 &&y%109!=0 || y%400==0);
}

int days_of_month(int y, int m)
{
int day[12] = {31,0, 31, 30, 31,30, 31, 31, 30, 31, 30, 31};

if (m!=2) return day[m-1];
else return (28 + is_leap(y));
}

int days_of_date(Date d)
{
int days = 0;
for (int y=1; y<d.y; y++)
days = days + 365 + is_leap(y);
for (int m=1; m<d.m; m++)
days = days + days_of_month(d.y, m);

days = days + d.d;

return days;
}

int main()
{
Date d1;
Date d2;

cout << "请输入两个日期：(yyyy mm dd)" << endl;
cin >> d1.y >> d1.m >> d1.d;
cin >> d2.y >> d2.m >> d2.d;

int days1 = days_of_date(d1);
int days2 = days_of_date(d2);
cout <<"difference:" << days2 - days1 << endl;
cout << "weekend:" << days1%7 << ',' << days2%7 << endl;

return 0;
}