Prince language on insect date class

1. Date class
   1. Date.h
   2. Date.cpp
   3. test.cpp
   4. Test situation
   5. Function add
      1. The date after the date plus the number of days
      2. Date plus days
      3. date ++,++ date
         1. In front of ++
         2. After ++
      4. The date minus the number of days
      5. Date minus days
      6. date –,-- date
         1. In front of –
         2. After –

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Date class

We should have the habit of writing code or projects == Write a little, make up a little ==, Form good habits , It is absolutely forbidden to edit after writing , Then he made a lot of mistakes and didn't want to see them , We first compile a minimum project or system framework to add other functions

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Date.h

Date.h Some file headers , Statement or something

#pragma once#include <iostream>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 	Date operator+(const int& day);	Date operator-(const int& day);private:	int _year;	int _month;	int _day;};

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Date.cpp

Date.cpp This is the function to write the date class

#include "Date.h"Date::Date(int year, int month, int day){	_year = year;	_month = month;	_day = day;}void Date::Print(){	cout << _year << " year " << _month << " month " << _day << " Japan " << endl;}Date Date::operator+(const int& day){	return *this;}Date Date::operator-(const int& day){	return *this;}

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test.cpp

test.cpp

#include "Date.h"int main(){	Date d(2022,1,1);	d.Print();	return 0;}

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Test situation

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Function add

When we can get out of the basic beggar version, we still have to go on the next road , We should consider whether the data is reasonable

== So we need to check the validity of the date ==

== The above does exclude percent 99 It's filtered out , But leap years 2 Month is a special consideration, but there is no code implementation ==

== Can we optimize , For example, if I input a wrong date and you die directly, is it a bit overbearing , You should throw an exception , Or an interval or something ==

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;}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;	}}void Date::Print(){	cout << _year << " year " << _month << " month " << _day << " Japan " << endl;}

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The date after the date plus the number of days

Date& Date::operator+=(const int& day){	// 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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Date plus days

== It's just adding and not assigning , You have to distinguish yourself from the one above , So I need an intermediate temporary variable （ We call this temporary object ） To store the calculated data ==

// 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;}

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date ++,++ date

== Both date plus and date plus are ++, however operator How to distinguish between operator overloads ,==

In front of ++

== In front of ++ Returns the value after the operation ==

//++d  Date before ++  Converted to d.operator++(&d)Date& Date::operator++(){	// Returns the value after the operation 	*this += 1;	return *this;}

After ++

== After ++ Returns the value before the operation ==

//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;}

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The date minus the number of days

// The date minus the number of days is assigned back at the same time Date& Date::operator-=(const int& day){	// 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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Date minus days

== Just reuse the above function ==

// Date minus days   Don't give it back Date Date::operator-(const int& day){	Date ret(*this);	//-= Reuse of 	ret -= day;	return ret;}

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date –,-- date

== Both date subtraction and subtraction date are –, however operator How to distinguish between operator overloads ,==

In front of –

== In front of – Returns the value after the operation ==

// Pre subtraction Date& Date::operator--(){	*this -= 1;	return *this;}

After –

== After – Returns the value before the operation ==

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