日期类的实现

Date.h

Test.cpp

测试代码Test.cpp

日期类的实现

代码分享

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, Date& d);
	friend istream& operator>>(istream& in, Date& d);

public:
	// 全缺省的构造函数
	Date(int year = 1, int month = 1, int day = 1);

	// 拷贝构造函数
	Date (const Date& d);

	// 赋值运算符重载
	// d2 = d3; -> d2.operator=(&d2, d3);
	Date& operator=(const Date& d);
	// 析构函数
	~Date();
	// 直接定义类里面，他默认是inline
	// 频繁调用
	//得到月的天数
	int GetMonthDay(int year, int month)
	{
		assert(month>0&& month<13);
		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))//千万不能少括号
		{
			return 29;
		}
		return MonthDay[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 ++ ();
	// 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，也不需要用
	// 这个参数仅仅是为了跟前置++构成重载区分
	Date operator ++ (int);

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

	Date& operator -- ();
	Date operator -- (int);
	// 流插入
	// 不建议，因为Date* this占据了一个参数位置，使用d<<cout不符合习惯
	//void operator<<(ostream& out);

	void Printf()const
	{
		cout << _year << "年" << _month << "月" << _day << "日" << endl;
	}

private:
	int _year = 1;
	int _month = 1;
	int _day = 1;
};

Test.cpp

#include"Date.h"

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

// 全缺省的构造函数
Date::Date(int year , int month , int day )
{
	_year = year;
	_month = month;
	_day = day;
	if (!CheckDate())
	{
		cout << "日期非法" << endl;
	}
}
//Date d2(d1);
//Date d2 = d1;
// 拷贝构造函数
Date::Date(const Date& d)
{
	_year = d._year;
	_month = d._month;
	_day = d._day;

}

// 赋值运算符重载
// d2 = d3; -> d2.operator=(&d2, d3);
Date& Date::operator=(const Date& d)
{
	_year = d._year;
	_month = d._month;
	_day = d._day;
	return *this;
}

// 析构函数
Date::~Date()
{
	_year = 1;
	_month = 1;
	_day = 1;
}



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);
}

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

		}
		if (this->_year == d._year && this->_month == d._month && this->_day < d._day)
		{
			return true;
		}

	}
	return false;
}
bool Date::operator > (const Date& d)const
{
	return (!(*this < d)) && *this != d;//易错,或者!(*this<=d),但是要在<=函数后面
}

bool Date::operator <=(const Date& d)const
{
	return *this < d || *this == d;
}
bool Date::operator >= (const Date& d)const
{
	return *this > d || *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 ++ ()
{
	*this += 1;
	return *this;

}
Date Date::operator ++ (int)
{
	Date tmp = *this;
	*this += 1;
	return tmp;
}

Date& Date::operator -= (int day)
{
	if(day<0)
	{
		return *this += -day;
	}
	_day -= day;
	while (_day < 1)
	{
		--_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;
}

//日期减日期
int Date::operator -(const Date& d)const
{
	int flag = 1;
	int count = 0;
	//假设this大，d小
	Date max = (*this);
	Date min = d;
	if (max < min)
	{
		max = d;
		min = (*this);
		flag = -1;
	}
	while (max>min)
	{
		++min;//一般用前置
		++count;
	}
	return count * flag;
}

Date& Date::operator -- ()
{
	*this -= 1;
	return *this;
}
Date Date::operator -- (int)
{
	Date tmp = *this;
	*this -= 1;
	return tmp;
}

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

istream& operator>>(istream& in, Date& d)
{
	cout << "请输入年，月，日" << endl;
	in >> d._year >> d._month >> d._day;
	if (!d.CheckDate())
	{
		cout << "日期非法" << endl;
	}

	return in;
}

测试代码Test.cpp

#include"Date.h"
using namespace std;


void Test1()
{
	Date d1(2022,6,21);
	Date d2 = d1;
	Date d3(2022,6,1);
	if (d3 < d1)
	{
		cout << "d3<d1" << endl;
	}
}

void Test2()
{
	Date d1(2024, 4, 21);
	Date d2 = d1;
	d2 += 3000;
	d2.Printf();
	Date d3 = d1 + 300;
	d3.Printf();
	Date d4= d3++;
	d4.Printf();
	++d3;
	d3.Printf();


}

void Test3()
{
	Date d1(2024,4,21);
	Date d2 = d1 - 5000;
	d1 -= 20;
	d1.Printf();
	d2.Printf();
}

void Test4()
{
	Date d1(2024,4,21);
	Date d2(2002,2,14);
	int day = d2 - d1;
	cout << day << "Ìì" << endl;
}

void Test5()
{
	Date d1(2024,4,21);
	Date d2=d1--;
	d2.Printf();
	d1.Printf();
	--d1;
	d1.Printf();
}

void Test6()
{
	Date d1(2024, 4, 14);
	Date d2 = d1 + 30000;

	// operator<<(cout, d1)
	cout << d1;
	cout << d2;

	cin >> d1 ;
	d2 = d1 + 30000;
	 
	cout << d1 << d2;
}
int main()
{
	/*Test6();*/
	Date d1(2024, 4, 21);
	Date d2(2024, 4, 21);
	if (d1 == d2)
	{
		cout << "d1 == d2" << endl;
	}

	return 0;
}