日期类(详细接口)

定义

#pragma once
#include<iostream>
using namespace std;
class Date
{
public:
	Date(int year = 1, int month = 1, int day = 1);
	void Print() const;
	int GetMonthDay(int year, int month);
	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+=(const int day);
	Date operator+(const int day);
	// 日期-天数
	Date operator-(int day);
	// 日期-=天数
	Date& operator-=(int day);
	// 后置--
	Date operator--(int);
	// 前置--
	Date& operator--();
	//前置++
	Date& operator++();
	//后置++
	Date operator++(int);
	// 日期-日期 返回天数
	int operator-(const Date& d);
	//输出该天星期几
	void PrintWeekDay();

	/*void operator<<(ostream& out);*/
	//友元函数，函数的声明必须放在类里面
	friend ostream& operator<<(ostream& out, const Date& d);
	friend istream& operator>>(istream& in, Date& d);
private:
	int _year;
	int _month;
	int _day;
};

实现

#include"Date.h"



int Date::GetMonthDay(int year, int month)
{
	static int MonthDayArrary[13] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };
	int day = MonthDayArrary[month];
	if (month == 2 && ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)))
	{
		day += 1;
	}
	return day;
}
Date::Date(int year, int month, int day)
{
	_year = year;
	_month = month;
	_day = day;

	if (!(year >= 0
		&& (month > 0 && month < 13)
		&& (day > 0 && day <= GetMonthDay(year, month))))
	{
		cout << "非法日期" << endl;
		Print();
	}
}
void Date::Print() const
{
	cout << _year << "-" << _month << "-" << _day << endl;
}
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) || (*this == d);
}
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 _year == d._year
		&& _month == d._month
		&& _day == d._day;
}
bool Date::operator!=(const Date& d)
{
	return _year != d._year
		|| _month != d._month
		|| _day != d._day;
	//return !(*this == d);
}
//+=
Date& Date::operator+=(const int day)
{
	_day += day;
	while (_day > GetMonthDay(_year, _month))
	{
		_day -= GetMonthDay(_year, _month);
		++_month;

		if (_month == 13)
		{
			_month = 1;
			_year++;
		}
	}
	return *this;
}

//+
Date Date::operator+(const int day)
{
	Date ret(*this);
	//ret.operator+=(day);
	ret += day;
	return ret;
}
//前置++
Date& Date::operator++()
{
	*this += 1;
	return *this;
}
//后置++
Date Date::operator++(int)
{
	//后置++天生多加了两次拷贝构造
	Date ret(*this);
	*this += 1;
	return ret;
}

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;
}

// 日期-天数
Date Date::operator-(int day)
{
	Date ret(*this);
	ret -= day;
	return ret;
}

// 后置--
Date Date::operator--(int)
{
	Date ret(*this);
	*this -= 1;
	return ret;
}
// 前置--
Date& Date::operator--()
{
	*this -= 1;
	return *this;
}
// 日期-日期 返回天数
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 count = 0;
	while (max != min)
	{
		min++;
		count++;
	}
	return count * flag;
}

void Date::PrintWeekDay()
{
	const char* arr[] = { "星期一", "星期二", "星期三", "星期四", "星期五","星期六","星期天" };
	Date start(1, 1, 1);
	int count = *this - start;
	cout << arr[count % 7] << endl;
}

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

ostream& operator<<(ostream& out, const Date& d)
{
	cout << d._year << "/" << d._month << "/" << d._day << endl;
	return out;
}

istream& operator>>(istream& in, Date& d)
{
	cin >> d._year;
	cin >> d._month;
	cin >> d._day;
	return in;
}