运算符重载之日期类的实现

接上一篇文章，废话不多说，直接上代码

Date.h

#pragma once
#include<iostream>
using namespace std;
#include<assert.h>

class Date 
{
	//友元函数声明
	friend ostream& operator<<(ostream& out, const Date& d);
	friend istream& operator>>(istream& in, Date& d);

public:
	Date(int year = 1900, int month = 1, int day = 1);
	void Print()const;

	//GetMonthDay函数频繁调用，直接定义类里面，默认是inline
	int GetMonthDay(int year, int month)
	{
		assert(month > 0 && month < 13);
		static int monthDayArray[13] = { -1,31,28,31,30,31,30,31,31,30,31,30,31 };

		if (month == 2 && ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)))
		{
			return 29;
		}
		else
		{
			return monthDayArray[month];
		}
	}

	bool CheckDate();

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

	Date& operator+=(int day);
	Date operator+(int day)const;

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

	//前置++
	Date& operator++();
	//后置++，为了区分，构成重载，给后置++强行增加了一个int形参。这里不需要写形参名，因为接收值是多少不重要
	//该参数仅仅是为了跟前置++构成重载区分
	Date operator++(int);

	Date& operator--();
	Date operator--(int);

private:
	int _year;
	int _month;
	int _day;
};

//重载函数
ostream& operator<<(ostream& out, const Date& d);
istream& operator>>(istream& in, Date& d);

Date.cpp

#include"Date.h"

bool Date::CheckDate()
{
	if (_month < 1 || _month>12 || _day<1 || _day>GetMonthDay(_year, _month))
	{
		return false;
	}
	else
	{
		return true;
	}
}

Date::Date(int year, int month, int day)
{
	_year = year;
	_month = month;
	_day = day;

	if (!CheckDate())
	{
		cout << "日期非法" << endl;
	}
}

void Date::Print()const
{
	cout << _year << "-" << _month << "-" << _day << endl;
}

bool Date ::operator<(const Date& d)const
{
	if (_year < d._year)
	{
		return true;
	}
	else if (_year == d._year)
	{
		if (_month < d._month)
		{
			return true;
		}
		else if (_month == d._month)
		{
			return _day < d._day;
		}
	}
	return false;
}

bool Date::operator<=(const Date& d)const
{
	return *this < d || *this == d;
}

bool Date::operator>(const Date& d)const
{
	return!(*this <= d);
}

bool Date::operator>=(const Date& d)const
{
	return !(*this < d);
}

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

bool Date::operator!=(const Date& d)const
{
	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 == 13)
		{
			++_year;
			_month = 1;
		}
	}
	return *this;
}

Date Date::operator+(int day)const
{
	Date tmp = *this;
	tmp += day;
	return tmp;
}

Date& Date::operator-=(int day)
{
	if (day < 0)
	{
		return *this += -day;
	}
	_day -= day;
	while (_day <= 0)
	{
		--_month;
		if (_month == 0)
		{
			_month = 12;
			_year--;
		}
		_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;
}

//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 (min != max)
	{
		++min;
		++n;
	}
	return n * flag;
}

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

istream& operator>>(istream& in, Date& d)
{
	cout << "请依次输入年月日：>";
	in >> d._year >> d._month >> d._day;
	if (!d.CheckDate())
	{
		cout << "日期非法" << endl;
	}
	return in;
}

Test.cpp 

#include"Date.h"
void TestDate1()
{
	Date d1(2024, 6, 26);
	Date d2 = d1 + 30000;
	d1.Print();
	d2.Print();

	Date d3(2024, 6, 26);
	Date d4 = d3 - 5000;
	d3.Print();
	d4.Print();

	Date d5(2024, 6, 26);
	d5 += -5000;
	d5.Print();
}

void TestDate2()
{
	Date d1(2024, 6, 26);
	Date d2 = ++d1;
	d1.Print();
	d2.Print();

	Date d3 = d1++;
	d1.Print();
	d3.Print();
}

void TestDate3()
{
	Date d1(2024, 6, 26);
	Date d2(2034, 6, 26);
	int n = d1 - d2;
	cout << n << endl;
}

void TestDate4()
{
	const Date d1(2024, 6, 26);
	d1.Print();

	d1 + 100;

	Date d2(2024, 6, 26);
	d2.Print();

	d2 += 100;

	d1 < d2;
	d2 < d1;
}

int main()
{
	void TestDate1();
	return 0;
}

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