Prince language under insect date category

Fix it bug

if -= If the date inside is negative

== Sometimes we need to consider that there are negative numbers in the date ==

== So we need to change the code , need += Code for , Direct appropriation ==

== Reuse is enough ==

// The date minus the number of days is assigned back at the same time Date& Date::operator-=(const int& day){	// It is also illegal to exceed the number of days per month 	// Reuse += that will do 	if (day < 0)	{		*this += -day;	}	else	{		// Say nothing more , Subtract the days first 		_day -= day;		// If it's not legal, wait until it's legal 		while (_day <= 0)		{			// First reduce the number of months 			_month--;			// First judge whether the month is zero , If yes, it will be years of operation 			if (_month <= 0)			{				_year--;				_month = 12;			}			// Then ask him to add the correct number of days in the month 			_day += GetMonthDay(_year, _month);		}	}		return *this;}

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if += If the date inside is negative

== alike += If there is a negative number in it, it is handled the same way ==

== So we also put -= Bring the code of ==

== In the same way, it can be reused ==

// Date plus days are assigned back at the same time Date& Date::operator+=(const int& day){	// Negative multiplexed -= Of 	if (day < 0)	{		*this -= -day;	}	else	{		// We don't care , Let's add the sky directly 		_day += day;		// Then judge whether it is legal 		while (_day > GetMonthDay(_year, _month))		{			// First, subtract the number of days in the current month 			_day -= GetMonthDay(_year, _month);			// Next month ++			_month++;			// If the month has passed, it will be a year ++			if (_month > 12)			{				_year++;				_month = 1;			}		}	}	return *this;}

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Comparison operator

Greater than >

==d1 > d2==

// Compare // Greater than  d1 > d2 convert to d1.operator>(&d1,d2)bool Date::operator>(const Date& d){	if (_year > d._year)	{		return true;	}	else if (_year == d._year)	{		if (_month > d._month)		{			return true;		}		else if(_month == d._month)		{			if (_day > d._day)				return true;		}	}	// It's not the case above false	return false;}

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be equal to == 

==d1 == d2==

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

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Greater than or equal to >= 

==d1 >= d2==

// Greater than or equal to bool Date::operator>=(const Date& d){	return *this > d || *this == d;}

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Less than < 

==d1 < d2==

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

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Less than or equal to <= 

==d1 <= d2==

// Less than or equal to bool Date::operator<=(const Date& d){	return !(*this > d);}

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It's not equal to != 

==d1 != d2==

// It's not equal to bool Date::operator!=(const Date& d){	return !(*this == d);}

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Life is real

We have to think about whether it is meaningful to subtract a date from a date

Is the date minus the date the difference in days , How do you operate this

// Date minus date // By counting   If the years decrease   Month minus month means you can't find the actual number of days int Date::operator-(const Date& d){	// First, let's assume that the previous big 	Date max = *this;	// So the back is small 	Date min = d;	// A symbol mark 	int flag = 1;	// If you are wrong, exchange 	if (max < min)	{		max = d;		min = *this;		flag = -1;	}	// When min And max The same time is the time to stop counting 	int count = 0;	while (min != max)	{		min++;		count++;	}	// When you come out, you return the count with the mark 	return count * flag;}

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Code

Date.h

Date.h

#pragma once#include <iostream>#include <assert.h>using std::cout;using std::cin;using std::endl;class Date{public:	Date(int year = 0, int month = 1, int day = 1);	void Print();	// Like deconstruction , Copy structure , Assignment overloading can be done without writing , Because the default generation is enough ,	// image Stack You need to write these three 	// Date plus   Minus days   Then assign values to the past at the same time 	Date& operator+=(const int& day);	Date& operator-=(const int& day);	// Date plus   Minus days   No assignment is required 	Date operator+(const int& day);	Date operator-(const int& day);	// Date before, after, plus 	Date& operator++();	Date& operator++(int);	// Date before date after date minus 	Date& operator--();	Date& operator--(int);	// Compare 	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 minus date 	int operator-(const Date& d);private:	int _year;	int _month;	int _day;};

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Date.cpp

Date.cpp

#include "Date.h"inline int GetMonthDay(int year, int month){	// The array stores the number of days of each month in a normal year   The corresponding subscript is month   The element inside is heaven 	static int dayArray[13] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };	// Days of the month 	int day = dayArray[month];	// Leap year is 4 Once a year, once a century, or once every 400 years 	if (month == 2 	&& (year % 4 == 0 && year % 100 != 0) 	|| year % 400 == 0)	{		// Leap year's 2 Month is 29 God 		day = 29;	}	return day;}// Constructors Date::Date(int year, int month, int day){	// Check the validity of the date 	if (year > 0	 && month > 0 && month <13	 && day > 0 && day <= GetMonthDay(year,month))	{		_year = year;		_month = month;		_day = day;	}	else	{		cout << endl;		cout << " Illegal date " << endl;		cout << year << " year " << month << " month " << day << " Japan " << endl;	}}// Date printing void Date::Print(){	cout << _year << " year " << _month << " month " << _day << " Japan " << endl;}// Date plus days are assigned back at the same time Date& Date::operator+=(const int& day){	// Negative multiplexed -= Of 	if (day < 0)	{		*this -= -day;	}	else	{		// We don't care , Let's add the sky directly 		_day += day;		// Then judge whether it is legal 		while (_day > GetMonthDay(_year, _month))		{			// First, subtract the number of days in the current month 			_day -= GetMonthDay(_year, _month);			// Next month ++			_month++;			// If the month has passed, it will be a year ++			if (_month > 12)			{				_year++;				_month = 1;			}		}	}	return *this;}// Date plus days   Don't give it back Date Date::operator+(const int& day){	// First create a temporary object   Copy the previous copy to him first 	Date ret(*this);	// Reuse +=	ret += day;	return ret;}//++d  Date before ++  Converted to d.operator++(&d)Date& Date::operator++(){	// Returns the value after the operation 	*this += 1;	return *this;}//d++  Post date ++  Converted to d.operator++(&d,0)// there int It's just space , You don't need to give arguments , Play the role of function overloading Date& Date::operator++(int){	// After ++ Returns the value before the operation 	// So you need to save a temporary object first 	Date tmp(*this);	*this += 1;	return tmp;}// The date minus the number of days is assigned back at the same time Date& Date::operator-=(const int& day){	// It is also illegal to exceed the number of days per month 	// Reuse += that will do 	if (day < 0)	{		*this += -day;	}	else	{		// Say nothing more , Subtract the days first 		_day -= day;		// If it's not legal, wait until it's legal 		while (_day <= 0)		{			// First reduce the number of months 			_month--;			// First judge whether the month is zero , If yes, it will be years of operation 			if (_month <= 0)			{				_year--;				_month = 12;			}			// Then ask him to add the correct number of days in the month 			_day += GetMonthDay(_year, _month);		}	}		return *this;}// Date minus days   Don't give it back Date Date::operator-(const int& day){	Date ret(*this);	//-= Reuse of 	ret -= day;	return ret;}// Pre subtraction Date& Date::operator--(){	*this -= 1;	return *this;}// Post subtraction Date& Date::operator--(int){	Date tmp(*this);	*this -= 1;	return tmp;}// Compare // Greater than  d1 > d2 convert to d1.operator>(&d1,d2)bool Date::operator>(const Date& d){	if (_year > d._year)	{		return true;	}	else if (_year == d._year)	{		if (_month > d._month)		{			return true;		}		else if(_month == d._month)		{			if (_day > d._day)				return true;		}	}	// It's not the case above false	return false;}// be equal to bool Date::operator==(const Date& d){	return _year == d._year		&& _month == d._month		&& _day == d._day;}// Greater than or equal to bool Date::operator>=(const Date& d){	return *this > d || *this == d;}// Less than bool Date::operator<(const Date& d){	return !(*this >= d);}// Less than or equal to bool Date::operator<=(const Date& d){	return !(*this > d);}// It's not equal to bool Date::operator!=(const Date& d){	return !(*this == d);}// Date minus date // By counting   If the years decrease   Month minus month means you can't find the actual number of days int Date::operator-(const Date& d){	// First, let's assume that the previous big 	Date max = *this;	// So the back is small 	Date min = d;	// A symbol mark 	int flag = 1;	// If you are wrong, exchange 	if (max < min)	{		max = d;		min = *this;		flag = -1;	}	// When min And max The same time is the time to stop counting 	int count = 0;	while (min != max)	{		min++;		count++;	}	// When you come out, you return the count with the mark 	return count * flag;}

test.cpp

test.cpp

#include "Date.h"void test1(){	// In front of ++ And post ++ It's all done ++, The difference is that the return value is different 	Date d(2022, 1, 1);	d ++;	// After ++ return ++ Previous value 	d.Print();	++d;	// In front of ++ return ++ Later value 	d.Print();}void test2(){	// In front of -- And post -- It's all done --, The difference is that the return value is different 	Date d(2022, 1, 1);	d--;	// After -- return -- Previous value 	d.Print();	--d;	// In front of -- return -- Later value 	d.Print();}void test3(){	Date d1(2022, 1, 2);	Date d2(2022, 1, 2);	cout << (d1 != d2) << endl;	d2 -= 1;	cout << (d1 != d2) << endl;}void test4(){	Date d1(2024, 1, 2);	Date d2(2022, 5, 7);	cout << d1 - d2 << endl;	cout << d2 - d1 << endl;}int main(){	test1();	test2();	test3();	test4();	Date d(2022,1,1);	d += -40;	d.Print();	Date d2(2022, 1, 1);	d2 += 4000;	d2.Print();	Date d3(2022, 1, 1);	d3 = d3 + 3000;	d3.Print();	Date d4(2022, 1, 1);	d4 -= -3000;	d4.Print();	Date d5(2022, 1, 1);	d5 = d5-2000;	d5.Print();	return 0;}