#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;
  }
  Date(int year = 1900, int month = 1, int day = 1)
  {
    _year = year;
    _month = month;
    _day = day;
  }
  void Print();
  bool operator==(const Date& d);
  bool operator!=(const Date& d);
  bool operator>(const Date& d);
  bool operator<(const Date& d);
  bool operator>=(const Date& d);
  bool operator<=(const Date& d);
  Date operator+(int day);
  Date& operator++();//默认是前置++，返回+完后的值，用引用返回
  Date operator++(int i);//后前置++，里面要写一个参数，这里的参数可以不用形参接收，括号里直接写int就行，但加了参数也无所谓,这里的参数只是为了区分
  //C++为了区分前后置++，使用重载进行区分，后置++重载增加一个int参数跟前置构成函数重载进行区分
  Date& operator+=(int day);
  Date operator-(int day);
  Date& operator-= (int day);
  Date& operator--();
  Date  operator--(int);
  int operator-(const Date& d);
private:
  int _year;
  int _month;
  int _day;
};

#include"date.h"
bool Date::operator==(const Date& d)
{
  return _year == d._year &&
    _month == d._month &&
    _day == d._day;
}
bool Date::operator!=(const Date& d)
{
  return !(*this == d);
}
bool Date::operator>(const Date& d)
{
  if (_year > d._year)
    return true;
  else if (_year == d._year && _month > d._month)
  {
    return true;
  }
  else if (_year == d._year && _month == d._month && _day > d._day)
  {
    return true;
  }
  else
    return false;
}
bool Date::operator<(const Date& d)
{
  return !(*this >= d);
}
bool Date::operator>=(const Date& d)
{
  return (*this > d) || (*this == d);
}
bool Date::operator<=(const Date& d)
{
  return !(*this > d);
}
// 自身要改变
Date&  Date::operator+=(int day)
{
  _day += day;
  while (_day > GetMonthDay(_year, _month))
  {
    _day -= GetMonthDay(_year, _month);
    _month++;
    if (_month == 13)
    {
      _month = 1;
      _year ++;
    }
  }
  return *this;
}
//自身不改变
Date  Date::operator+(int day)
{
  Date ret(*this);//拷贝构造
  //Date ret= *this;在这里，这条语句是拷贝构造，拿*this初始化ret，已经存在的对线才是赋值
  ret += day;
  return ret;//传值返回的时候，会生成一份拷贝
}
void  Date::Print()
{
  cout << _year<<"/" << _month<<"/"<<_day << endl;
}
Date& Date::operator++()//前置
{
  *this += 1;
  return *this;
}
Date Date::operator++(int)//后置,返回++之前的值
{
  Date tmp(*this);
  *this += 1;
  return tmp;
}
Date& Date::operator-= (int day)
{
  _day -= day;
  while (_day <= 0)
  {
    --_month;
    if (_month == 0)
    {
      --_year;
      _month = 12;
    }
    _day += GetMonthDay(_year,_month);
  }
  return *this;
}
Date Date::operator-(int day)
{
  Date ret = *this;
  ret -= day;
  return ret;
}
Date& Date::operator--()//前置--
{
  *this -= 1;
  return *this;
}
Date   Date::operator--(int)//后置--
{
  Date tmp = *this;
  *this -= 1;
  return tmp;
}
int  Date::operator-(const Date& d)//日期相减
{
  int flag = 1;
  Date max = *this;
  Date min = d;
  if (*this < d)
  {
    min = *this;
    max = d;
    flag = -1;
  }
  int n = 0;
  while (min != max)
  {
    ++min;
    ++n;
  }
  return n*flag;
}

int main()
{
  Date d1(2001, 1, 3);
  Date d2(2023, 7, 23);
  Date d3(2022, 6, 23);
  cout << (d1 < d2) << endl;
  cout << (d1 > d2) << endl;
  cout << (d1 == d2) << endl;
  cout << (d1 < d3) << endl;
  cout << (d1 > d3) << endl;
  cout << (d1 == d3) << endl;
  Date ret1 = d1 + 100;
  ret1.Print();
  Date ret2=++d1;//转换为d1.operator++(&d1)
  ret2.Print();
  Date ret3=d2++;//转换为d1.operator++(&d2,0)
  ret3.Print();
  d1 += 100;
  d1.Print();
  d1 -= 100;
  d1.Print();
  Date ret4 = d1 - 1000;
  ret4.Print();
  int ret5 = d1 - d2;
  cout << ret5 << endl;
  return 0;
}

  Date(int year = 1900, int month = 1, int day = 1)
  {
    _year = year;
    _month = month;
    _day = day;
         //assert(CheckDate());
    if (!CheckDate())
    {
      Print();
      cout << "日期非法" << endl;
    }
  }
  bool CheckDate()
  {
    if (_year >= 1 && _month < 13 && _month>0 && _day > 0 && _day <= GetMonthDay(_year, _month))
      return true;
    else
      return false;
  }

Date&  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)
    {
      _month = 1;
      _year ++;
    }
  }
  return *this;
}

void Date::operator<<(ostream& out)
{
  out << _year << "-" << _month << _day;
}