题解 | 日期差值

#include <iostream>
using namespace std;
#include<assert.h>
class Date
{
public:
    Date(int year = 1,int month = 1,int day = 1)
        :_year(year)
        ,_month(month)
        ,_day(day)
    {}
    inline int GetMonthDay(int year, int month)
    {
        assert(month > 0 && month < 13);
        static int monthDayArray[13] = { -1, 31, 28, 31, 30, 31, 30, 31, 31, 30,31, 30,  31 };

        // 365天 5h +
        if (month == 2 && ((year % 4 == 0 && year % 100 != 0) || (year % 400 ==0)))
        {
            return 29;
        }
        else
        {
            return monthDayArray[month];
        }
    }

    bool operator>(const Date& d)
    {
        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;
        }
        else 
        {
            return false;
        }
    }

    bool operator==(const Date& d)
    {
        return _day == d._day   
            && _month == d._month
            && _year == d._year;
    }  

    bool operator!=(const Date& d)
    {
        return !((*this) == d);
    }

    Date& operator+=(int day)
    {
        _day += day;
        // =不执行，比如下个月28，则就是x月28天
        while(_day>GetMonthDay(_year,_month))
        {
            _day -= GetMonthDay(_year, _month);
            ++_month;
            if(_month == 13)
            {
                _month = 1;
                ++_year;
            }
        }
        return *this;
    }

//两个年月日相差多少天
    int operator-(const Date& d)
    {
        Date max = *this;
        Date min = d;
        if(min>max)
        {
            max = d;
            min = *this;
        }
        int count = 0;
        while(min!=max)
        {
            min += 1;
            count++;
        }
        return count;
    }
private:
    int _year;
    int _month;
    int _day;
};

int main() {
    int year1,month1,day1;
   // cin>>year1>>month1>>day1;  //这个输入过不去
    scanf("%4d%2d%2d",&year1,&month1,&day1);
    int year2,month2,day2;       //这个输入过不去
     scanf("%4d%2d%2d",&year2,&month2,&day2);
   // cin>>year2>>month2>>day2;

    Date d1 = {year1,month1,day1};
    Date d2 = {year2,month2,day2};
    //有点奇怪，为啥都少一天，在这儿加了个1，就行了
    //知道的告诉我原因
    cout<< d1-d2+1;
    return 0;
}
// 64 位输出请用 printf("%lld")