c++日期类

#include <iostream>using namespace std;class Date{public:Date(int year = 2017, int month = 9, int day = 20): _year(year), _month(month), _day(day){}Date& operator=(const Date& d);// 前置++ Date& operator++();// 后置++ Date operator++(int);Date& operator--();Date operator--(int);//days天之后的日期 Date operator+(int days);// days天之前的日期 Date operator-(int days);// 两个日期之间的距离 int operator-(const Date& d);bool operator==(const Date& d);bool operator!=(const Date& d);bool operator>(const Date& d);bool operator<(const Date& d);private:int _year;int _month;int _day;};Date&  Date::operator=(const Date& d){if (this != &d){this->_year = d._year;this->_month = d._month;this->_day = d._day;}return *this;}Date& Date::operator++(){if ((this->_month == 1) || (this->_month == 3)|| (this->_month == 5) || (this->_month == 7)|| (this->_month == 8) || (this->_month == 10)|| (this->_month == 12)){if ((this->_day == 31)&&(this->_month) != 12){this->_month += 1;this->_day = 1;}else if ((this->_day == 31) && (this->_month) == 12){this->_year += 1;this->_month = 1;this->_day = 1;}else{this->_day += 1;}}else if (this->_month == 2){if (((this->_year % 4 == 0) && (this->_year % 100 != 0)) || (this->_year % 400 == 0)){if (this->_day == 29){this->_month += 1;this->_day = 1;}else{this->_day += 1;}}else{if (this->_day == 28){this->_month += 1;this->_day = 1;}else{this->_day += 1;}}}else{if (this->_day == 30){this->_month += 1;this->_day = 1;}else{this->_day += 1;}}return *this;}Date Date::operator++(int){Date temp;temp = *this;if ((this->_month == 1) || (this->_month == 3)|| (this->_month == 5) || (this->_month == 7)|| (this->_month == 8) || (this->_month == 10)|| (this->_month == 12)){if ((this->_day == 31) && (this->_month) != 12){this->_month += 1;this->_day = 1;}else if ((this->_day == 31) && (this->_month) == 12){this->_year += 1;this->_month = 1;this->_day = 1;}else{this->_day += 1;}}else if (this->_month == 2){if (((this->_year % 4 == 0) && (this->_year % 100 != 0)) || (this->_year % 400 == 0)){if (this->_day == 29){this->_month += 1;this->_day = 1;}else{this->_day += 1;}}else{if (this->_day == 28){this->_month += 1;this->_day = 1;}else{this->_day += 1;}}}else{if (this->_day == 30){this->_month += 1;this->_day = 1;}else{this->_day += 1;}}return temp;}Date& Date::operator--(){if ((this->_month == 2) || (this->_month == 4)|| (this->_month == 6) || (this->_month == 7)|| (this->_month == 9) || (this->_month == 11)){if (this->_day == 1){this->_month -= 1;this->_day = 31;}else{this->_day -= 1;}}else if (this->_month == 3){if (((this->_year % 4 == 0) && (this->_year % 100 != 0)) || (this->_year % 400 == 0)){if (this->_day == 1){this->_month -= 1;this->_day = 29;}else{this->_day -= 1;}}else{if (this->_day == 1){this->_month -= 1;this->_day = 28;}else{this->_day -= 1;}}}else{if ((this->_month == 1)&& this->_day == 1){_year -= 1;_month = 12;_day = 31;}else if (this->_day == 1){this->_month -= 1;this->_day = 30;}else{this->_day -= 1;}}return *this;}Date Date::operator--(int){Date temp;temp = *this;if ((this->_month == 2) || (this->_month == 4)|| (this->_month == 6) || (this->_month == 8)|| (this->_month == 9) || (this->_month == 11)){if (this->_day == 1){this->_month -= 1;this->_day = 31;}else{this->_day -= 1;}}else if (this->_month == 3){if (((this->_year % 4 == 0) && (this->_year % 100 != 0)) || (this->_year % 400 == 0)){if (this->_day == 1){this->_month -= 1;this->_day = 29;}else{this->_day -= 1;}}else{if (this->_day == 1){this->_month -= 1;this->_day = 28;}else{this->_day += 1;}}}else{if (this->_day == 1){this->_month -= 1;this->_day = 30;}else{this->_day -= 1;}}return temp;}Date Date::operator+(int days){Date temp;temp = *this;while (days--){++temp;}return temp;}Date Date::operator-(int days){Date temp;temp = *this;while (days--){--temp;}return temp;}bool Date::operator==(const Date& d){if ((this->_year) == (d._year)){if ((this->_month) == (d._month)){if ((this->_day) == (d._day)){return 1;}else{return 0;}}else{return 0;}}else{return 0;}}int Date::operator-(const Date& d){int count = 0;Date temp = *this;if (temp == d){return 0;}else{while (temp != d){if (temp > d){--temp;count++;}else{++temp;count++;}}return count;}}bool Date::operator!=(const Date& d){if (*this == d){return 0;}else{return 1;}}bool Date::operator>(const Date& d){if ((this->_year) > (d._year)){return 1;}else if ((this->_year) == (d._year)){if ((this->_month) > (d._month)){return 1;}else if (this->_month == d._month){if (this->_day > d._day){return 1;}else{return 0;}}else{return 0;}}else{return 0;}}bool Date::operator<(const Date& d){if (*this > d){return 0;}else if (*this == d){return 0;}else{return 1;}}int main(){Date ret(2017, 9, 21);Date temp(2016,8, 21);int x;ret++;temp = ret + 100;x = ret - temp;printf("%d\n", x);system("pause");return 0;}


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