题解 | #日期差值# 日期类秒了

#include <iostream>
using namespace std;

class Date
{
public:
    Date(int year = 0, int month = 0, int day = 0)
        :_year(year)
        , _month(month)
        , _day(day)
    {

    }
    int GetMonthDay(int year, int month)
    {
        static int tomonth[13] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };
        if (month == 2 && (year % 4 == 0 && year % 100 != 0 || year % 400 == 0))
        {
            return 29;
        }
        return tomonth[month];
    }
    bool operator>(const Date& d) const
    {
        return !(*this <= d);
    }
  
    bool operator<(const Date& d) const
    {
        if (_year < d._year)
        {
            return true;
        }
        else if (_year == d._year)
        {
            if (_month < d._month)
            {
                return true;
            }
            else if (_month == d._month)
            {
                if (_day < d._day)
                {
                    return true;
                }
            }
        }
        return false;
    }
  	bool operator<=(const Date& d) const
	{
		return (*this < d && *this = d);
	}
    bool operator==(const Date& d) const
    {
        return _year == d._year
            && _month == d._month
            && _day == d._day;
    }
    bool operator!=(const Date& d) const
    {
        return !(*this == d);
    }
    Date& operator+=(int day)
    {
        _day += day;
        while (_day > GetMonthDay(_year, _month))
        {
            if (_month > 12)
            {
                _year++;
                _month = 1;
            }
            _day -= GetMonthDay(_year, _month);
            _month++;
        }
        return *this;
    }
    Date& operator++()
    {
        *this += 1;
        return *this;
    }
    //两个日期相减
    int operator-(Date& d) const 
    {
        //假设两日期哪个大
        Date max = *this;
        Date min = d;
        //int flag = 1;
        if (max < min)
        {
            max = d;
            min = *this;
            //flag = -1;
        }
        int ret = 0;
        while (max != min)
        {
            ret++;
            ++min;
        }
        //ret *= flag;
        return ret + 1;
    }
    int YearToDay()
    {
        Date ToYear(_year, 1, 1);
        // 如果两数相减，得到的是中间的差值；10 - 1 = 9；实际是10天
        int Day = 1 + (*this - ToYear);
        return Day;
    }
private:
    int _year;
    int _month;
    int _day;
};

int main()
{
    int date1 = 0;
    int date2 = 0;
    cin >> date1 >> date2;
    Date d1(date1 / 10000,(date1 % 10000) / 100,date1 % 100);
    Date d2(date2 / 10000,(date2 % 10000) / 100,date2 % 100);
    cout << d1 - d2 << endl;
    return 0;
}