题解 | 日期差值

#include <ratio>
#define _CRT_SECURE_NO_WARNINGS 1
#pragma once
#include<iostream>
#include<stdbool.h>
#include<assert.h>
//#include<stdio.h>
using namespace std;
class Date {
  public:
    friend ostream& operator<<(ostream& out, const Date& d);
    friend istream& operator>>(istream& in, Date& d);
    void Print()const {
        cout << _year << "/" << _month << "/" << _day << endl;
    }
    bool CheckDate();
    // 获取某年某月的天数

    int GetMonthDay(int year, int month) {
        assert(month > 0 && month < 13);
        static int array[13] = { -1, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
        if (month == 2 && year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
            return 29;
        }
        return array[month];

    }
    // 全缺省的构造函数
    Date(int year = 1900, int month = 1, int day = 1) {

        _year = year;
        _month = month;
        _day = day;
        if (!CheckDate()) {
            cout << "日期非法" << endl;
        }
        //cout << "11111" << endl;
    }

    // 拷贝构造函数

    //Date d2(d1);

    Date(const Date& d) {
        _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);


    // 析构函数
    //~Date();
    // 日期+=天数
    Date& operator+=(int day);
    // 日期+天数
    Date operator+(int day)const;
    // 日期-天数
    Date operator-(int day)const;
    // 日期-=天数
    Date& operator-=(int day);



    // 前置++

    Date& operator++();



    // 后置++

    Date operator++(int);



    // 后置--

    Date operator--(int);



    // 前置--

    Date& operator--();



    // >运算符重载

    bool operator>(const Date& d)const;



    // ==运算符重载

    bool operator==(const Date& d)const;



    // >=运算符重载

    bool operator >= (const Date& d)const;



    // <运算符重载

    bool operator < (const Date& d)const;



    // <=运算符重载

    bool operator <= (const Date& d)const;



    // !=运算符重载

    bool operator != (const Date& d)const;



    // 日期-日期 返回天数

    int operator-(const Date& d)const;

  private:

    int _year;

    int _month;

    int _day;

};
ostream& operator<<(ostream& out, const Date& d);
istream& operator>>(istream& in, Date& d);
Date parseDate(long long dateStr) {
    int year = dateStr / 10000;
    int month = (dateStr % 10000) / 100;
    int day = dateStr % 100;
    return Date(year, month, day);
}
// 日期+=天数
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 > 12) {
            _year++;
            _month = 1;
        }
    }
    return *this;
}
// 日期+天数
Date Date::operator+(int day)const {
    Date tmp = *this;
    tmp += day;

    return tmp;
}

Date& Date:: operator=(const Date& d) {
    _year = d._year;
    _month = d._month;
    _day = d._day;

    return *this;
}
// 日期-天数

Date Date::operator-(int day)const {
    Date tmp = *this;
    tmp -= day;

    return tmp;
}

// 日期-=天数

Date& 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;
}

// >运算符重载

bool Date::operator>(const Date& d)const {
    return !(*this <= d);
}

// ==运算符重载

bool Date::operator==(const Date& d)const {
    return _year == d._year
           && _month == d._month
           && _day == d._day;
}
// >=运算符重载

bool Date::operator >= (const Date& d)const {
    return !(*this < d);
}
// <运算符重载

bool Date::operator < (const Date& d)const {
    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;
}
// <=运算符重载

bool Date::operator <= (const Date& d)const {
    return *this < d || *this == d;
}

// !=运算符重载

bool Date::operator != (const Date& d)const {

    return !(*this == d);
}

// 前置++

Date& Date::operator++() {
    *this += 1;

    return *this;
}



// 后置++

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

}



// 后置--

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



// 前置--

Date& Date::operator--() {

    *this -= 1;
    return *this;
}

// 日期-日期 返回天数

int Date::operator-(const Date& d)const {
    Date max = *this;
    Date min = d;
    int flag = 1;
    if (*this < d) {
        max = d;
        min = *this;
        flag = -1;
    }
    int n = 0;
    while (min < max) {
        n++;
        min++;
    }
    return n * flag;
}

//防止玩家恶搞
bool Date::CheckDate() {
    if (_month < 1 || _month > 12
            || _day < 1 || _day > GetMonthDay(_year, _month)) {
        return false;
    } else {
        return true;
    }
}



ostream& operator<<(ostream& out, const Date& d) {
    out << d._year << "年" << d._month << "月" << d._day << "日" << endl;
    return out;
}
istream& operator>>(istream& in, Date& d) {
    while (1) {
        cout << "请依次输入年月日:>";
        in >> d._year >> d._month >> d._day;
        if (!d.CheckDate()) {
            cout << "日期非法" << endl;
            d.Print();
            cout << "请重新输入" << endl;
        } else {
            break;
        }
    }
    return in;
}
int main() {

    long long day1, day2;
    while (cin >> day1 >> day2) {
        Date d1 = parseDate(day1);
        Date d2 = parseDate(day2);
        int day3=abs(d1-d2)+1;
        printf("%d\n",day3);

        
    }

    return 0;
}