#include <iostream>
#include <sstream>
#include <iomanip>

using namespace std;

unsigned int daysOfMonth1[] = { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
unsigned int daysOfMonth2[] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

struct Date {
    unsigned int year;
    unsigned int month;
    unsigned int day;
};

void display(Date d) {
    cout << "year: " << d.year << "; ";
    cout << "month: " << d.month << "; ";
    cout << "day: " << d.day << endl;
}

void read(Date& d) {
    cout << "Enter year" << endl;
    cin >> d.year;

    cout << "Enter month" << endl;
    cin >> d.month;

    cout << "Enter day" << endl;
    cin >> d.day;
}

void init(Date& d, unsigned int year, unsigned int month, unsigned int day) {
    d.year = year;
    d.month = month;
    d.day = day;
}

void init(Date& d, string date) { // 2020.03.31
    stringstream str(date);
    char symbol;
    str >> d.year >> symbol >> d.month >> symbol >> d.day;
}

string toString(Date d) {
    stringstream str;
    str << d.year << "." << setprecision(2) << d.month << "." << setprecision(2) << d.day;
    return str.str();
}

bool isLeapYear(Date& date) {
    return (date.year % 4 == 0);
}

void setYear(Date& date, unsigned int year) {
    date.year = year;
}

unsigned int getYear(Date& date) {
    return date.year;
}

void setMonth(Date& date, unsigned int month) {
    date.month = month;
}

unsigned int getMonth(Date& date) {
    return date.month;
}

void setDay(Date& date, unsigned int day) {
    date.day = day;
}

unsigned int getDay(Date& date) {
    return date.day;
}

bool isDateEquals(Date& date1, Date& date2) {
    if (date1.year != date2.year) {
        return false;
    }

    if (date1.month != date2.month) {
        return false;
    }

    if (date1.day != date2.day) {
        return false;
    }

    return true;
}

bool isDateGreate(Date& date1, Date& date2) {
    if (date1.year < date2.year) {
        return false;
    }

    if (date1.year == date2.year) {
        if (date1.month < date2.month) {
            return false;
        }

        if (date1.month == date2.month) {
            if (date1.day <= date2.day) {
                return false;
            }
        }
    }

    return true;
}

bool isDateLess(Date& date1, Date& date2) {
    if (date1.year > date2.year) {
        return false;
    }

    if (date1.year == date2.year) {
        if (date1.month > date2.month) {
            return false;
        }

        if (date1.month == date2.month) {
            if (date1.day >= date2.day) {
                return false;
            }
        }
    }

    return true;
}

unsigned int convertDateToDays(Date& date) {
    unsigned int days = 0;

    for (int year = 0; year < date.year; year++) {
        if (year % 4 == 0) days += 366;
        else days += 365;
    }

    for (int month = 1; month < date.month; month++) {
        if (date.year % 4 == 0) days += daysOfMonth1[month];
        else days += daysOfMonth2[month];
    }

    days += date.day;

    return days;
}

unsigned int getDaysBetweenDates(Date& date1, Date& date2) {
    if (isDateEquals(date1, date2)) return 0;
    int days = convertDateToDays(date1) - convertDateToDays(date2);

    return (days > 0) ? (days) : (-days);
}

void addDay(Date& date, unsigned int days) {
    if (days == 0) return;

    for (int i = 1; i <= days; i++) {
        if (isLeapYear(date)) {
            if (date.day > daysOfMonth1[date.month]) {
                date.day %= daysOfMonth1[date.month];

                if (date.month == 12) {
                    date.month = 1;
                    date.year++;
                }
                else {
                    date.month++;
                }
            }
        }
        else if (date.day > daysOfMonth2[date.month]) {
            date.day %= daysOfMonth2[date.month];

            if (date.month == 12) {
                date.month = 1;
                date.year++;
            }
            else {
                date.month++;
            }
        }

        date.day++;
    }
}

string isCompareDates(Date& date1, Date& date2) {
    if (isDateEquals(date1, date2)) return "равны";
    if (isDateGreate(date1, date2)) return "больше";
    if (isDateGreate(date1, date2)) return "меньше";

    return "неизвестно";
}

void subDay(Date& date, unsigned int days) {
    if (days == 0) return;

    for (int i = 1; i <= days; i++) {
        if (date.day == 1) {
            if (date.month == 1) date.month = 12;
            else date.month--;

            if (isLeapYear(date)) date.day = daysOfMonth1[date.month];
            else date.day = daysOfMonth2[date.month];
        }
        else date.day--;
    }
}

int main() {
    setlocale(LC_ALL, "rus");
    Date a;
    read(a);
    display(a);

    Date b;
    init(b, 2020, 31, 03);
    display(b);

    Date c;
    init(c, "2020.03.31");
    display(c);

    addDay(a, 2);
    display(a);

    subDay(b, 2);
    display(b);
}