c++日期类的实现（基础篇）

基本功能实现：

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

Date operator+(int day);
Date operator+=(int day);
Date operator-(int day);
Date operator-=(int day);
Date operator++();
Date operator++(int);
Date operator--();
Date operator--(int); 

#include <iostream>#include <assert.h>using namespace std;class Date{public:Date(int year = 1900, int month = 1, int day = 1){_year = year;_month = month;_day = day;}void Display(){cout << _year << "-" << _month << "-" << _day << endl;}bool Isvalue(){if (_month > 0 && _month<13 &&_day<=GetMonthday() && _day>0&& _year>0)return true;elsereturn false;}bool operator<(const Date &d2){assert(Isvalue());if (_year < d2._year){return true;}else if (_month < d2._month){return true;}else if (_day < d2._day){return true;}elsereturn false;}bool operator>(const Date &d2){assert(Isvalue());if (_year > d2._year){return true;}else if (_month > d2._month){return true;}else if (_day > d2._day){return true;}elsereturn false;}bool operator<=(const Date &d2){return !(*this > d2);}bool operator>=(const Date &d2){return !(*this<d2);}bool operator!=(const Date &d2){return ((*this<d2)||(*this>d2));}bool operator==(const Date &d2){return !((*this<d2)||(*this>d2));}int GetMonthday(){int monthDays[13] = { 0, 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;elsereturn monthDays[_month];}Date operator+(int day){if (day<0){return *this - (-day);}Date tmp(*this);tmp._day += day;while (tmp._day >tmp.GetMonthday()){tmp._day -= tmp.GetMonthday();tmp._month++;if (tmp._month > 12){tmp._year++;tmp._month = 1;}}return tmp;}Date operator-(int day){if (day<0){return *this + (-day);}Date tmp(*this);tmp._day -= day;while (tmp._day <= 0){tmp._month--;if (tmp._month == 0){tmp._year--;tmp._month = 12;}tmp._day += tmp.GetMonthday();}return tmp;}Date &operator=(const Date &d){if ((*this != d)){_year = d._year;_month = d._month;_day = d._day;}return *this;}Date& operator++(){*this += 1;return *this;}Date operator++(int){Date tmp(*this);*this += 1;return tmp;}Date& operator--(){*this -= 1;return *this;}Date operator--(int){Date tmp(*this);*this -= 1;return tmp;}Date &operator+=(int day){if (day < 0){return (*this = *this - day);}*this = *this + day;return *this;}Date &operator-=(int day){if (day < 0){return (*this = *this +(-day));}*this = *this - day;return *this;}int operator-(const Date &d){int tag = 1;Date big(*this);Date less(d);if (*this < d){big = d;less = *this;tag = -1;}int count = 0;while (big>less){++count;less++;}return count*tag;}private:int _year;int _month;int _day;};int main(){Date d1(2017, 10, 26);Date d2(2017, 2, 14);d1.Display();d2.Display();cout << (d1.operator<(d2)) << endl;cout << (d1.operator>(d2)) << endl;cout << (d1.operator<=(d2)) << endl;cout << (d1.operator>=(d2)) << endl;cout << (d1.operator!=(d2)) << endl;cout << (d1.operator==(d2)) << endl;Date d3 = d1 + 2000;d3.Display();Date d4 = d1 - 52000;d4.Display();d1 += 6;d1.Display();d1 -= 6;d1.Display();d1++;d1.Display();++d1;d1.Display();d1--;d1.Display();--d1;d1.Display();d2 = d1 - 100;cout<<(d1-d2)<<endl;}

运行结果：