C++实现日期类

#include <iostream>
using namespace std;
class Date
{
public:
	// 获取某年某月的天数
	int GetMonthDay(int year, int month)
	{
		static int days[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
		int day = days[month];
		if (month == 2&& ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)))
		{
			day += 1;
		}
		return day;
	}
	// 全缺省的构造函数

	Date(int year = 1900, int month = 1, int day = 1)
	{
		if (year < 1900|| month < 1 || month > 12|| day < 1 || day > GetMonthDay(year, month))
		{
			cout << "日期不符合实际" << endl;
		}
		_year = year;
		_month = month;
		_day = day;
	}
	// 拷贝构造函数
  // d2(d1)
	Date(const Date& d)
	{
		this->_year = d._year;
		_month = d._month;
		_day = d._day;
	}
// 赋值运算符重载
  // d2 = d3 -> d2.operator=(&d2, d3)
	Date& operator=(const Date& d)
	{
		if (this != &d)
		{
			this->_year = d._year;
			this->_month = d._month;
			this->_day = d._day;
		}
		return *this;
	}
	// 析构函数
	~Date()
	{
	}
	void Print()
	{
		cout << _year << "|" << _month << "|" << _day << endl;
	}
// 日期+=天数
	Date& operator+=(int day)
	{
		if (day < 0)
		{
			return *this -= -day;
		}
		_day += day;
		while (_day > GetMonthDay(_year, _month))
		{
			_day -= GetMonthDay(_year, _month);
			_month++;
			if (_month == 13)
			{
				_year++;
				_month = 1;
			}
		}
		return *this;
	}
// 日期+天数
	Date operator+(int day)
	{
		Date ret(*this);
		ret += day;
		return ret;
	}
// 日期-天数
	Date operator-(int day)
	{
		Date ret(*this);
		ret -= day;
		return ret;
	}
// 日期-=天数
	Date& operator-=(int day)
	{
		if (day < 0)
		{
			return *this += -day;
		}
		_day -= day;
		while (_day <= 0)
		{
			--_month;
			if (_month == 0)
			{
				--_year;
				_month = 12;
			}
			_day += GetMonthDay(_year, _month);
		}
		return *this;
	}	
// 前置++
	Date& operator++()
	{
		*this += 1;
		return *this;
	}
// 后置++

	Date operator++(int)
	{
		Date ret(*this);
		*this += 1;
		return ret;
	}
// 后置--
	Date operator--(int)
	{
		Date ret(*this);
		*this -= 1;
		return ret;
	}
// 前置--
	Date& operator--()
	{
		*this -= 1;
		return *this;
	}
	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)
			{
				if (_day > d._day)
				{
					return true;
				}
			}
		}
		return false;
	}
	bool operator==(const Date& d)
	{
		return _year == d._year
			&& _month == d._month
			&& _day == d._day;
	}
	inline bool operator >= (const Date& d)
	{
		return *this > d || *this == d;
	}
	bool operator < (const Date& d)
	{
		return !(*this >= d);
	}
	bool operator <= (const Date& d)
	{
		return !(*this > d);
	}
	bool operator != (const Date& d)
	{
		return !(*this == d);
	}
// 日期-日期 返回天数
	int operator-(const Date& d)
	{
		int flag = 1;
		Date max = *this;
		Date min = d;
		if (*this < d)
		{
			max = d;
			min = *this;
			flag = -1;
		}
		int day = 0;
		while (min < max)
		{
			++(min);
			++day;
		}
		return day * flag;
	}
private:
	int _year;
	int _month;
	int _day;

};
int main() {
	Date d1(2022,2,26);
	Date d2(2022,3,26);
	return 0;
}