#include<iostream>
#include<windows.h>

using namespace std;

class Date
{
public:
	Date(int year, int month, int day) //建構函式
		:_year(year)
		,_month(month)
		,_day(day)
	{}
	Date(Date & d)   //拷貝構造
		:_year(d._year)
		, _month(d._month)
		, _day(d._day)
	{}
	Date & operator = (const Date &d) //賦值運算子的過載
	{//將例項d的所有成員變數值全部賦值給this,這裡不存在指標問題，就不用考慮記憶體問題
		_year = d._year;
		_month = d._month;
		_day = d._day;
		return *this;
	}
	bool operator == (const Date& d)//過載 ==
	{
		return this->_year == d._year
			&& this->_month == d._month
			&& this->_day == d._day;
	}
	bool operator <(const Date& d) //過載 <
	{
		if (_year < d._year)//判斷年
		{
			return true;
		}
		else if (_year == d._year)//年相等，就判斷月
		{
			if (_month<d._month)
			{
				return true;
			}
			else if (_month == d._month)//月相等，判斷天
			{
				if (_day<d._day)
				{
					return true;
				}
			}
		}
		return false;
	}
	bool operator <=(const Date& d)//過載<=(複用函式<和==)
	{
		return (*this<d) || (*this == d);//當<或==滿足一個的時候為真
	}
	bool operator >(const Date& d)//過載<=(複用函式<=)
	{
		return !(*this <= d);
	}
	bool operator >=(const Date& d)
	{
		return !(*this < d);
	}
	Date operator+ (int day)//過載+
	{
		int ret = GetMonthDay(_year, _month);//呼叫函式獲取當年當月天數
		Date tmp = *this;//用this建立一個臨時物件
		while ((_day + day) > ret)//迴圈條件：當總天數大於一個月的天數時
		{
			if ((tmp._month + 1) > 12)//當月份大於12時
			{
				tmp._year++;//年份加一
				tmp._month = 0;//月份置零
			}
			else//否則，月份加一
			{
				tmp._month++;
			}
			day -= ret;//總天數減去當月的天數
			ret = GetMonthDay(_year, tmp._month);//獲取下一月的天數
		}
		tmp._day += day;
		return tmp;
	}
	Date& operator+= (int day)//過載+=（複用+）
	{
		*this = *this + day;
		return *this;
	}

	Date operator- (int day)//過載-
	{
		int ret = GetMonthDay(_year, _month);
		Date tmp = *this;
		while (day > tmp._day)//當需要減的天>當月的天數時進行迴圈
		{
			while (day > ret)
			{
				if (tmp._month > 1)
				{
					tmp._month--;
				}
				else
				{
					tmp._year--;
					tmp._month = 11;
				}
				day -= ret;
				ret = GetMonthDay(tmp._year, tmp._month);
			}
			day -= ret;
		}
		tmp._day -= day;
		return tmp;
	}
	Date& operator-= (int day)//過載-=（複用-）
	{
		*this = *this - day;
		return *this;
	}

	Date operator++()
	{
		return *this += 1;
	}
	Date operator++(int)
	{
		return *this + 1;
	}

	Date operator--()
	{
		return *this -= 1;
	}
	Date operator--(int)
	{
		return *this - 1;
	}

	int operator-(const Date& d)//日期間日期
	{
		Date tmp = *this;
		int day = 0;
		int ret = 0;
		if (tmp > d)
		{
			while (tmp._year > d._year)
			{
				if (tmp._month > 2)
				{
					if (IsLeapYear(tmp._year))
					{
						day += 366;
						tmp._year--;
					}
				}
				else
				{
					day += 365;
					tmp._year--;
				}
			}
			while (tmp._month > d._month)
			{
				ret = GetMonthDay(tmp._year, tmp._month);
				day += ret;
			}
			if (tmp._day > d._day)
			{
				day += tmp._day - d._day;
			}
			else
			{
				day -= d._day - tmp._day;
			}

		}
		return day;
	}
	void Display()
	{
		cout << _year << "\t" << _month << "\t" << _day << endl;
	}
protected:
	bool IsLeapYear(int year)//判斷是否為閏年
	{
		if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
		{
			return true;
		}
		return false;
	}
	int GetMonthDay(int year, int month)//獲得當年當月天數
	{
		int monthArray[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

		int day = monthArray[month];

		if (month == 2 && IsLeapYear(year))
		{
			day += 1;
		}
		return day;
	}
private:
	int _year;
	int _month;
	int _day;
};