hw10_02.cpp

#include <iostream>
#include<cmath>
#include<ctime>

using namespace std;
class MyDate {
    public:
    MyDate(unsigned long second = time(0)) {
        int days = dayfromsecond(second);
        timefromday(days);
    }
    MyDate(int y, int m, int d) {
        year = y;
        month = m;
        day = d;
    }
    void showtime() {
        cout<<"Y:"<<year<<endl;
        cout<<"M:"<<month<<endl;
        cout<<"D:"<<day<<endl;
    }
    int dayfromsecond(unsigned long seconds) {
        return seconds / (24 * 60 * 60);
    }
    bool leapyear(int years) {
        return  (years % 4 == 0 && years % 100 != 0) || (years % 400 == 0);
    }
    void timefromday(int days) {
        year=1970, month=1, day=1;
        while (true) {
            int daymonth[]={31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
            if (leapyear(year)) daymonth[1] = 29;
            days-=daymonth[month-1];
            if (days < 0){
                day+=days+daymonth[month-1];
                return;
            }
            month+=1;
            if (month == 13) {
                year+=1;
                month=1;
            }
        }
    }
    private:
    int year, month, day;
};

int main() {
    MyDate d1,d2(3456201512),d3(2023,11,9);
    cout<<"默认情况"<<endl;
    d1.showtime();
    cout<<"秒数指定"<<endl;
    d2.showtime();
    cout<<"时间指定"<<endl;
    d3.showtime();
    return 0;
}