题解 | #日期累加# C++

using namespace std;

class Date
{
    friend istream& operator>>(istream& cin, Date& d);

private:
    int _year;
    int _month;
    int _day;

public:
    Date(int year = 1200, int month = 1, int day = 1)
        :_year(year),
        _month(month),
        _day(day)
    { }

    static int GetMonthDay(int year, int month)
    {
        static int dayArr[] = {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;
        }
        else {
            return dayArr[month];
        }
    }

    Date& operator+=(const int day)
    {
        _day += day;
        while(_day > GetMonthDay(_year, _month))
        {
            _day -= GetMonthDay(_year, _month);
            ++_month;
            if(_month > 12)
            {
                ++_year;
                _month = 1;
            }
        }

        return *this;
    }

    void Print() const
    {
        printf("%04d-%02d-%02d\n", _year, _month, _day);
    }
};

istream& operator>>(istream& cin, Date& d)
{
    cin >> d._year >> d._month >> d._day;
    return cin;
}

int main()
{
    int n = 0;
    cin >> n;
    while(n--)
    {
        Date d;
        int day = 0;
        cin >> d >> day;
        d += day;
        d.Print();
    }
    return 0;
}