C++ Date类运算符重载

布满荆棘的人生 2024-04-18 22:28 63阅读 0赞

##  C++ Date类运算符重载 ##

> \+=, -=, -(两日期相减), -(日期-天数), +, ++(前置), ++(后置), --(前置), --(后置), =,  <<,  >>, <, >, <=, >=, !=, ==
> 
> 值得注意的是, 闰年并不是4年一闰, 我们通常习惯理解为4年一闰  
> 闰年判断条件 (**year % 400 == 0 ||** (**year % 4 == 0 && year % 100**)), 可以看到, 当年份是4的倍数, 但可以被100整除, 且不能被400整除时, 并不是闰年, 例如2096年是闰年, 按习惯2100年是闰年, 但2100年不能满足判断条件,不是闰年,下一个闰年是2104, 相隔8年, 还可以发现 2100,2200,2300,2500,2600,2700,2900等等都不是闰年, 遇到这种年份前后闰年相隔8年

#pragma once
    #include<iostream>
    using namespace std;
    class Date{
    	int m_year;
    	int m_month;
    	int m_day;
    	static int m_s_months[12];
    public:
    	Date(int y = 2019, int m = 10, int d = 1) :
    		m_year(y),
    		m_month(m),
    		m_day(d) 
    	{
    	}
    	Date& operator=(const Date& t);
    	friend ostream& operator<<(ostream& os, const Date& t);
    	friend istream& operator>>(istream& os, Date& t);
    	bool operator<(const Date& t)const;
    	bool operator>(const Date& t)const;
    	bool operator==(const Date& t)const;
    	bool operator!=(const Date& t)const;
    	bool operator<=(const Date& t)const;
    	bool operator>=(const Date& t)const;
    	Date& operator+=(size_t n);//计算当前日期+n天的日期值, 再将这个值给自己
    	Date operator+(size_t n)const;//n天之后的日期
    	Date operator-(size_t n)const;//n天之前的日期
    	Date& operator-=(size_t n);//计算当前日期-n天的日期值, 再将这个值给自己
    	int operator-(const Date& t)const;//两个日期之间差几天
    	Date& operator++();
    	Date& operator--();
    	Date operator++(int);
    	Date operator--(int);
    
    	static int getMonthDay(int y, size_t n);//返回y年n月的天数
    	bool LeapYear(int year)const;
    	int countLeapYear(int year)const;
    };

#include"Date.h"
    int Date::m_s_months[12] = { 31,28,31,30,31,30,31,31,30,31,30,31 };
    int Date::getMonthDay(int y, size_t n) {
    	return m_s_months[n-1]+ (n == 2 && (y % 400 == 0 || (y % 4 == 0 && y % 100)));
    }
    Date& Date::operator=(const Date& t) {
    	if (this != &t) {
    		m_year = t.m_year;
    		m_month = t.m_month;
    		m_day = t.m_day;
    	}
    	return *this;
    }
    ostream& operator<<(ostream& os, const Date& t) {
    	os << t.m_year << "年" << t.m_month << "月" << t.m_day << "日";
    	return os;
    }
    istream& operator>>(istream& os, Date& t) {
    	printf("请输入年份\n");
    	while (1) {
    		os >> t.m_year;
    		if (t.m_year >= 0) {
    			break;
    		}
    		cout << "年份必须非负,请重新输入年份\n";
    	}
    	cout << "请输入月份\n";
    	while (1) {
    		os >> t.m_month;
    		if (t.m_month < 1) {
    			cout << "月份必须大于0, 请重新输入\n";
    			continue;
    		}
    		if (t.m_month > 12) {
    			cout << "月份必须小于等于12, 请重新输入\n";
    			continue;
    		}
    		break;
    	}
    	cout << "请输入日\n";
    	while (1) {
    		os >> t.m_day;
    		if (t.m_day < 1) {
    			cout << "请输入大于0的天数\n";
    			continue;
    		}
    		if (t.m_day > Date::getMonthDay(t.m_year,t.m_month)) {
    			cout << "你输入的号数大于本月天数" << Date::getMonthDay(t.m_year, t.m_month) << "请重新输入\n";
    			continue;
    		}
    		break;
    	}
    	return os;
    }
    bool Date::operator<(const Date& t)const {
    	if (this == &t) {
    		return false;
    	}
    	if (m_year < t.m_year) {
    		return true;
    	}
    	if (m_year == t.m_year && m_month < t.m_month) {
    		return true;
    	}
    	if (m_month == t.m_month && m_day < t.m_day) { 
    		return true;
    	}
    	return false;
    }
    bool Date::operator>(const Date& t)const {
    	if (this == &t) {
    		return false;
    	}
    	if (m_year > t.m_year) {
    		return true;
    	}
    	if (m_year == t.m_year && m_month > t.m_month) {
    		return true;
    	}
    	if (m_month == t.m_month && m_day > t.m_day) {
    		return true;
    	}
    	return false;
    }
    bool Date::operator!=(const Date& t)const {
    	if (this == &t) {
    		return false;
    	}
    	return (m_year != t.m_year) || (m_month != t.m_month) || (m_day != t.m_day);
    	//或者
    	//return !(*this == t);
    }
    bool Date::operator==(const Date& t)const {
    	if (this == &t) {
    		return true;
    	}
    	return (m_year == t.m_year) && (m_month == t.m_month) && (m_day == t.m_day);
    	//或者
    	//return !(*this != t);
    }
    bool Date::operator<=(const Date& t)const {
    	if (this == &t) {
    		return true;
    	}
    	if (m_year > t.m_year) {
    		return false;
    	}
    	else if (m_year == t.m_year && m_month > t.m_month) {
    		return false;
    		if (m_month == t.m_month && m_day > t.m_day) {
    			return false;
    		}
    	}
    	return true;
    	//或者
    	//return *this == t || *this < t;
    }
    bool Date::operator>=(const Date& t)const {
    	if (this == &t) {
    		return true;
    	}
    	if (m_year < t.m_year) {
    		return false;
    	}
    	else if (m_year == t.m_year && m_month < t.m_month) {
    		return false;
    		if (m_month == t.m_month && m_day < t.m_day) {
    			return false;
    		}
    	}
    	return true;
    	//或者
    	//return *this == t || *this > t;
    }
    Date& Date::operator++() {
    	if (m_day == getMonthDay(m_year, m_month)) {
    		m_day = 1;
    		m_month == 12 ? m_month = 1, ++m_year : ++m_month;
    	}
    	else {
    		++m_day;
    	}
    	return *this;
    }
    Date& Date::operator--() {
    	if (m_day == 1) {
    		m_month == 1 ? m_month = 12, --m_year : --m_month;
    		m_day = getMonthDay(m_year, m_month);
    	}
    	else {
    		--m_day;
    	}
    	return *this;
    }
    Date Date::operator++(int) {
    	Date tmp = *this;
    	if (m_day == getMonthDay(m_year, m_month)) {
    		m_day = 1;
    		m_month == 12 ? m_month = 1, ++m_year : ++m_month;
    	}
    	else {
    		++m_day;
    	}
    	return tmp;
    }
    Date Date::operator--(int) {
    	Date tmp = *this;
    	if (m_day == 1) {
    		m_month == 1 ? m_month = 12, --m_year : --m_month;
    		m_day = getMonthDay(m_year, m_month);
    	}
    	else {
    		--m_day;
    	}
    	return tmp;
    }
    bool Date::LeapYear(int year) const{
    	return year % 400 == 0 || (year % 4 == 0 && year % 100);
    }
    Date& Date::operator+=(size_t n) {
    	size_t count = 0;
    	for (int i = 1; i < (int)m_month; ++i) {
    		count += getMonthDay(m_year, i);
    	}
    	count += m_day;
    	if (n >= (365 + LeapYear(m_year) - count)) { 
    		n -= (365 + LeapYear(m_year) - count);
    		m_month = 12;
    		m_day = 31;
    		while ((int)n >= (365 + LeapYear(m_year + 1))) {
    			n -= (365 + LeapYear(++m_year));
    		}
    	}
    	for (;n > 0; --n) {
    		if (m_day == getMonthDay(m_year, m_month)) {
    			m_day = 1;
    			m_month == 12 ? m_month = 1, ++m_year: ++m_month;
    		}
    		else {
    			++m_day;
    		}
    	}
    	return *this;
    }
    Date Date::operator+(size_t n)const {
    	Date tmp = *this;
    	size_t count = 0;
    	for (int i = 1; i < (int)tmp.m_month; ++i) {
    		count += getMonthDay(tmp.m_year, i);
    	}
    	count += tmp.m_day;
    	if (n >= (365 + LeapYear(tmp.m_year) - count)) {
    		n -= (365 + LeapYear(tmp.m_year) - count);
    		tmp.m_month = 12;
    		tmp.m_day = 31;
    		while ((int)n >= (365 + LeapYear(tmp.m_year + 1))) {
    			n -= (365 + LeapYear(++tmp.m_year));
    		}
    	}
    	for (; n > 0; --n) {
    		if (tmp.m_day == getMonthDay(tmp.m_year, tmp.m_month)) {
    			tmp.m_day = 1;
    			tmp.m_month == 12 ? tmp.m_month = 1, ++tmp.m_year : ++tmp.m_month;
    		}
    		else {
    			++tmp.m_day;
    		}
    	}
    	return tmp;
    }
    Date Date::operator-(size_t n)const {
    	Date tmp = *this;
    	size_t count = 0;
    	for (int i = 1; i < (int)tmp.m_month; ++i) {
    		count += getMonthDay(tmp.m_year, i);
    	}
    	count += m_day;
    	if (n >= count) {
    		n -= count;
    		tmp.m_month = 12;
    		tmp.m_day = 31;
    		--tmp.m_year;
    		while ((int)n >= (365 + LeapYear(tmp.m_year))) {
    			n -= (365 + LeapYear(tmp.m_year--));
    		}
    	}
    	for (; n > 0; --n) {
    		if (tmp.m_day == 1) {
    			if (tmp.m_month == 1) {
    				tmp.m_day = getMonthDay(--tmp.m_year, 12);
    			}
    			else {
    				tmp.m_day = getMonthDay(tmp.m_year, --tmp.m_month);
    			}
    		}
    		else {
    			--tmp.m_day;
    		}
    	}
    	return tmp;
    }
    Date& Date::operator-=(size_t n) {
    	size_t count = 0;
    	for (int i = 1; i < (int)m_month; ++i) {
    		count += getMonthDay(m_year, i);
    	}
    	count += m_day;
    	if (n >= count) {
    		n -= count;
    		m_month = 12;
    		m_day = 31;
    		--m_year;
    		while ((int)n >= (365 + LeapYear(m_year))) {
    			n -= (365 + LeapYear(m_year--));
    		}
    	}
    	for (; n > 0; --n) {
    		if (m_day == 1) {
    			if (m_month == 1) {
    				m_day = getMonthDay(--m_year, 12);
    			}
    			else {
    				m_day = getMonthDay(m_year, --m_month);
    			}
    		}
    		else {
    			--m_day;
    		}
    	}
    	return *this;
    }
    int Date::countLeapYear(int year)const {
    	if (m_year == year) {
    		return LeapYear(year);
    	}
    	int begin = m_year;
    	int end = year - 1;
    	if (m_year > year) {
    		begin = year;
    		end = m_year - 1;
    	}
    	while (!(LeapYear(begin))) {
    		++begin;
    	}
    	while (!(LeapYear(end))) {
    		--end;
    	}
    	int tmp = begin;
    	int count = 0;
    	if (begin <= end) {
    		while (tmp <= end && tmp % 100) { 
    			++tmp;;
    		}
    		for (; tmp <= end; !LeapYear(tmp) ? ++count : count, tmp += 100);
    		return (end - begin) / 4 + 1 - count;
    	}
    	return 0;
    }
    
    int Date::operator-(const Date& t)const {
    	Date mindate = *this;
    	Date maxdate = t;
    	if (mindate > maxdate) {
    		maxdate = *this;
    		mindate = t;
    	}
    	int count = 0;
    	if (maxdate.m_year > mindate.m_year) {
    		count += countLeapYear(t.m_year) + (maxdate.m_year - mindate.m_year) * 365;
    	}
    	for (int i = 1; i < (int)mindate.m_month; ++i) {
    		count -= getMonthDay(mindate.m_year, i);
    	}
    	count -= mindate.m_day;
    
    	for (int i = 1; i < (int)maxdate.m_month; ++i) {
    		count += getMonthDay(maxdate.m_year, i);
    	}
    	count += maxdate.m_day;
    	return count;
    }

#include"Date.h"
    void test1() {
    	Date a;
    	Date c;
    	Date b;
    	cout << "输入a:\n";
    	cin >> a;
    	cout << "a:" << a << endl;
    	cout<< "输入b:\n";
    	cin >> b;
    	c = b;
    	cout << "b:" << b << endl;
    	cout << "c:" << c << endl;
    	a > b ? cout << a << ">" << b << endl : cout << a << "<=" << b << endl;
    	a < b ? cout << a << "<" << b << endl : cout << a << ">=" << b << endl;
    	a >= b ? cout << a << ">=" << b << endl : cout << a << "<" << b << endl;
    	a <= b ? cout << a << "<=" << b << endl : cout << a << ">" << b << endl;
    	b == c ? cout << b << "==" << c << endl : cout << b << "!=" << c << endl;
    	a != c ? cout << a << "!=" << c << endl : cout << a << "==" << c << endl;
    	system("pause");
    	system("cls");
    }
    void test2() {
    	Date a;
    	Date b;
    	Date c;
    	size_t n = 1000000000;
    	cout << "输入a\n";
    	cin >> a;
    	c = a;
    	cout << "a:" << a << endl;
    	a += n;
    	cout << "a:" << a << endl;
    	cout << a - c << endl;
    	c = a;
    	a -= n;
    	cout << "a:" << a << endl;
    	b = a + n;
    	cout << "a:" << a << endl;
    	cout << "b:" << b << endl;
    	b = b - n;
    	cout << "a:" << a << endl;
    	cout << "b:" << b << endl;
    	cout << "a:" << ++a << endl;
    	cout << "a:" << a << endl;
    	cout << "a:" << a++ << endl;
    	cout << "a:" << a << endl;
    	cout << "a:" << --a << endl;
    	cout << "a:" << a << endl;
    	cout << "a:" << a-- << endl;
    	cout << "a:" << a << endl;
    }
    int main() {
    	test1();
    	test2();
    	system("pause");
    	return 0;
    }

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