C++—日期类的实现+运算符重载_6-1 日期类输出运算符重载

Date.h

#pragma once
#include<iostream>
using namespace std;

class Date
{
public:

	//获取某年某月的天数
	int GetMonthDay(int year, int month)
	{
		static int MonthDay[13] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };     //建立12个月天数的数组

		//判断是否是闰年的二月份
		if (month == 2&& ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)))
		{
			return 29;
		}
		else
		{
			return MonthDay[month];
		}
	}

	//全缺省构造函数
	Date(int year=1997,int month=10,int day=20)
	{
		_year = year;
		_month = month;
		_day = day;

		//检查输入的日期是否合法
		if (!(year >= 1 && year <= 12) && (month >= 1 && month <= 12) 
			&& (day >= 1 && day <= GetMonthDay(year, month)))
		{
			cout << "非法日期" << endl;
		}
	}


	析构函数
	//~Date();

	//拷贝构造函数
	Date(const Date& d)
	{
		_year = d._year;
		_month = d._month;
		_day = d._day;
	}

	//赋值运算符重载
	Date& operator=(const Date& d)
	{
		if (*this != d)
		{
			_year = d._year;
			_month = d._month;
			_day = d._day;
		}
		return *this;
	}

	void Print()
	{
		cout << _year << "-" << _month << "-" << _day << endl;
	}
	//==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+=天数
	Date& operator+=(int day);

	//日期+天数
	Date operator+(int day) const;

	//日期-=天数
	Date& operator-=(int day);

	//日期-天数
	Date operator-(int day) const;

	//前置
	Date& operator++();

	//后置
	Date operator++(int);

	//前置
	Date& operator--();

	//后置
	Date operator--(int);

	//日期-日期
	int operator-(const Date& d) const;


private:
	int _year;
	int _month;
	int _day;
};
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Date.cpp

#include "Date.h"

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

bool Date::operator>(const Date& d) const
{
	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;
	}

	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);
}

//<=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 !(*this == d);
}

//日期+=天数
Date& Date::operator+=(int day) 
{
	if (day < 0)
	{
		return *this -= abs(day);
	}

	_day += day;
	while(_day > GetMonthDay(_year, _month))
	{
		_day -= GetMonthDay(_year, _month);
		++_month;
	}
	if (_month == 13)
	{
		++_year;
		_month = 1;
	}
}

//日期+天数
Date Date::operator+(int day) const
{
	Date ret(*this);     //拷贝构造
	ret+= day;
	return ret;
}

//日期-=天数
Date& Date::operator-=(int day)
{
	if (day < 0)
	{
		return *this += abs(day);
	}

	day -= _day;
	while (day <= 0)
	{
		--_month;
		if (_month == 0)
		{
			--_year;
			_month = 0;
		}
		
		_day += GetMonthDay(_year, _month);
	}
}

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

//前置
Date& Date::operator++()
{
	*this += 1;
	return *this;
}

//后置
Date Date::operator++(int)
{
	Date ret(*this);
	ret += 1;
	return ret;
}

//前置
Date& Date::operator--()
{
	*this -= 1;
	return *this;
}
//后置
Date Date::operator--(int)
{
	Date ret(*this);
	ret -= 1;
	return ret;
}

//日期-日期
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 (max == min)
	{
		min++;
		++n;
	}

	return n * flag;
}
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main.cpp

#include "Date.h"

int main()
{
	Date d1;
	Date d2(d1);

	d2.Print();

	return 0;
}
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