【C++中日期类的实现】

一路，一路，一路从泥泞到风景...............................................................................................

前言

一、【什么是日期类】

二、【代码实现】

1.【Date.h】部分：

2.【Date.cpp】部分：

3.【Test.cpp】部分：

总结

前言

本篇是日期类的编写，望多多指正。

一、【什么是日期类】

在学习完类和对象之后，可以试着编写一个日期类进行练习，使得该类能够加减天数，计算两个日期之间相差的天数，还可以比较两个类之间的大小。

二、【代码实现】

1.【Date.h】部分：

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <iostream>
#include <stdbool.h>
#include <assert.h>
using namespace std;
class Date
{
public:friend ostream& operator<<(ostream& out, const Date& d);friend istream& operator>>(istream& in, Date& d);int GetMonthDay(int year, int month);Date(int year = 1, int month = 1, int day = 1);Date(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);bool operator!=(const Date& d);Date& operator+=(int day);Date operator+(int day)const;Date operator-(int day)const;Date& operator-=(int day);Date& operator++();Date operator++(int);Date operator--(int);Date& operator--();int operator-(const Date& d);
private:int _year;int _month;int _day;
};

2.【Date.cpp】部分：

#include "Date.h"
int Date::GetMonthDay(int year, int month)
{const static int MonthDay[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;}return MonthDay[month];
}
Date::Date(int year, int month, int day)
{_year = year;_month = month;_day = day;if (year < 1 || month < 1 || month>12 || day<1 || day>GetMonthDay(year,month)){cout << "error date" << endl;exit(-1);}
}
Date::Date(const Date& d)
{_year = d._year;_month = d._month;_day = d._day;
}
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 (_year == d._year) && (_month == d._month) && (_day == d._day);
}
bool Date::operator<=(const Date& d)
{return (*this < d) || (*this == d);
}
bool Date::operator>(const Date& d)
{return !(*this <= d);
}
bool Date::operator>=(const Date& d)
{return !(*this < d);
}
bool Date::operator!=(const Date& d)
{return !(*this == d);
}
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;
}
Date Date::operator+(int day)const
{Date tmp(*this);tmp += day;return tmp;
}
//Date Date::operator-(int day)
//{
//	Date tmp(*this);
//	tmp._day -= day;
//	while (tmp._day <= 0)
//	{
//		tmp._month--;
//		if (tmp._month < 1)
//		{
//			tmp._year--;
//			tmp._month = 12;
//		}
//		tmp._day += tmp.GetMonthDay(tmp._year, tmp._month);
//	}
//	return tmp;
//}
//Date& Date::operator-=(int day)
//{
//	*this = *this - day;
//	return *this;
//}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;
}Date Date::operator-(int day) const
{Date tmp(*this);tmp -= day;return tmp;
}
Date& Date::operator++()
{*this += 1;return *this;
}Date Date::operator++(int)
{Date tmp(*this);*this += 1;return tmp;
}Date& Date::operator--()
{*this -= 1;return *this;
}Date Date::operator--(int)
{Date tmp(*this);*this -= 1;return tmp;
}
int Date::operator-(const Date& d)
{Date Max = *this;Date Min = d;int flag = 1;if (*this < d){Max = d;Min = *this;flag = -1;}int n = 0;while (Min != Max){Min++;n++;}return flag * n;}
ostream& operator<<(ostream& out, const Date& d)
{out << d._year << "/" << d._month << "/" << d._day << endl;return out;
}istream& operator>>(istream& in, Date& d)
{in >> d._year >> d._month >> d._day;return in;
}

3.【Test.cpp】部分：

#define _CRT_SECURE_NO_WARNINGS
#include "Date.h"
int main()
{Date d1(2023,7,1);Date d2(2023, 7, 28);cout << d1 << endl;cout << d2 << endl;cout << (d2-d1) << endl;cout << (++d2) << endl;cout << (d2++) << endl;cout << d2 << endl; cout << (d1--) << endl;cout << (--d1) << endl;Date sum = d2 + 260;cout << sum << endl;cout << (d2+=480) << endl;return 0;
}