题解 | #日期差值#

#include <climits>
#include <iostream>
#include <iterator>
#include <assert.h>
using namespace std;

class date
{
public:
    int getmonthday(int year, int month)
    {
        assert(month > 0 && month < 13);

        static int arr[13] = { -1,31,28,31,30,31,30,31,31,30,31,30,31 };

        if (month == 2 && ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)))
        {
            return 29;
        }
        else
        {
            return arr[month];
        }
    }
    date(int year = 1949, int month = 1, int day = 1)
    {
        _year = year;
        _month = month;
        _day = day;
    }
    bool operator==(const date& d)
    {
        return d._day == _day
            && _month == d._month
            && _year == d._year;
    }
    bool operator!=(const date& d)
    {
        return !(*this == d);
    }
    date& operator+=(int day)
    {
        _day += day;
        while (_day > getmonthday(_year, _month))
        {
            _day -= getmonthday(_year, _month);
            _month++;
            if (_month == 13)
            {
                _year++;
                _month = 1;
            }
        }

        return *this;
    }
        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)
		{
			return _day > d._day;
		}
	}

	return false;
}
    int operator-(const date& d)const
{
	int flag = 1;
	date max = *this;
	date min = d;
	if (d > *this)
	{
		max = d;
		min = *this;
		flag = -1;
	}

	int n = 1;
	while (min != max)
	{
		min+=1;
		++n;
	}

	return n;
}

private:
    int _year;
    int _month;
    int _day;

};

int main() {
    
    int day1,day2,mon1,mon2,year1,year2;
    scanf("%4d%2d%2d",&year1,&mon1,&day1);
    scanf("%4d%2d%2d",&year2,&mon2,&day2);
    date d1(year1, mon1, day1);
    date d2(year2,mon2,day2);
    cout<< d1 - d2<<endl;


}