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1.日期类的实现接口(date.h)

对于多次调用的函数，我们会实现在头文件中，以提高效率(我会包含在其次标题中)； 

class Date

{

public:

// 获取某年某月的天数

int GetMonthDay(int year, int month);

  // 全缺省的构造函数

Date(int year = 1900, int month = 1, int day = 1);

  // 拷贝构造函数

// d2(d1)

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();

  // 日期+=天数

Date& operator+=(int day);

  // 日期+天数

Date operator+(int day);

  // 日期-天数

Date operator-(int day);

   // 日期-=天数

Date& operator-=(int day);

  // 前置++

Date& operator++();

  // 后置++

Date operator++(int);

  // 后置--

Date operator--(int);

  // 前置--

Date& operator--();

  // >运算符重载

bool operator>(const Date& d);

  // ==运算符重载

bool operator==(const Date& d);

  // >=运算符重载

bool operator >= (const Date& d);

  // <运算符重载

bool operator < (const Date& d);

   // <=运算符重载

bool operator <= (const Date& d);

  // !=运算符重载

bool operator != (const Date& d);

  // 日期-日期 返回天数

int operator-(const Date& d);

private:

int _year;

int _month;

int _day;

};

1.1 GetMonthDay

int GetMonthDay(int year, int month)
{

    //静态变量
    static int monthDayArray[13] = { -1, 31, 28, 31, 30, 31, 30,31, 31, 30, 31, 30, 31 };
    //判断是否为闰年

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

1.2 swap

注：在往后的C++使用中，多以引用代替指针，以防对NULL指针的解引用 

1.2.1 Date类的交换函数 

void swap(Date& A) {Date tmp = *this;*this = A;A = *this;
}

 1.2.2 年月日的交换函数

void swap(int* x, int* y) {int tmp = *x;*x = *y;*y = tmp;
}

2.日期类的实现接口(date.cpp)

获取某年某月的天数 

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

年月日的打印

void Date::Print() {cout << _year << '/' << _month << '/' << _day << endl;
}

2.1 重载运算符(operate)

2.1.1 operate+=

//+=
Date& Date::operator+=(int day) {_day += day;//当day大于该月的日期while (_day>GetMonthDay(_year,_month)) {_day -= GetMonthDay(_year, _month);_month++;//判断是否大于12月if (_month = 13) {_year++;_month = 1;}}return *this;
}

2.1.2 operate+

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

2.1.3 operate<（<=，>，>=以此类推）

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

2.1.4 operate-=

Date& Date::operator-=(int day)
{//如果day为负号，则+=或者+if (day < 0){return *this += (-day);}//先减值_day -= day;while (_day <= 0){--_month;//防止month过0if (_month == 0){_month = 12;--_year;}//先-month是因为取天数，是在上个月中取，并非当前月_day += GetMonthDay(_year, _month);}return *this;
}

2.1.5 operate-

int Date::operator-(const Date& d) {int y1, m1, d1, y2, m2, d2;int arr[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };y1 = this->_year;m1 = this->_month;d1 = this->_day;y2 = d._year;m2 = d._month;d2 = d._day;int sum2 = 0;int sum1 = 0;if (y1 < y2) {swap(&y1, &y2);swap(&m1, &m2);swap(&d1, &d2);}if (y1 == y2) {if (m1 < m2) {swap(&m1, &m2);swap(&d1, &d2);}}if (y1 == y2) {if (m1 == m2) {if (d1 < d2) {swap(&d1, &d2);}}}//差的年数int x = y1 - y2;//记录2年的天数if (((y2 % 4 == 0) && (y2 % 100 != 0)) || y2 % 400 == 0) {//判断是否为闰年arr[1] = 29;}for (int i = 0; i < m2 - 1; i++) {sum2 += arr[i];}sum2 += d2;//记录1年的天数if (((y1 % 4 == 0) && (y1 % 100 != 0)) || y1 % 400 == 0) {//判断是否为闰年arr[1] = 29;}for (int i = 0; i < m1 - 1; i++) {sum1 += arr[i];}sum1 += d1;for (int i = 0; i < x; i++) {if (((y1 % 4 == 0) && (y1 % 100 != 0)) || y1 % 400 == 0) {sum1 += 366;}else {sum1 += 365;}}return sum1 - sum2;
}

2.2 拷贝构造

因为其内部没有空间的开辟，所以编译器默认的拷贝构造(浅拷贝)也可以使用

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

总结：

date.h

#pragma once#include<iostream>
using namespace std;
#include<assert.h>class Date
{
public:Date(int year = 1900, int month = 1, int day = 1);void Print();int GetMonthDay(int year, int month){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;}return monthDayArray[month];}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 operator+(int day);Date& operator+=(int day);Date& operator-=(int day);Date operator-(int day);// 日期-日期 返回天数int operator-(const Date& d);void swap(Date& A) {Date tmp = *this;*this = A;A = *this;}int getDays(const Date& d);void swap(int* x, int* y) {int tmp = *x;*x = *y;*y = tmp;}Date(const Date& d);
private:int _year;int _month;int _day;
};

date.cpp

#define _CRT_SECURE_NO_WARNINGS
#include"date.h"Date::Date(int year, int month, int day) {_year = year;_month = month;_day = day;
}void Date::Print() {cout << _year << '/' << _month << '/' << _day << endl;
}//+=
Date& Date::operator+=(int day) {_day += day;//当day大于该月的日期while (_day>GetMonthDay(_year,_month)) {_day -= GetMonthDay(_year, _month);_month++;//判断是否大于12月if (_month = 13) {_year++;_month = 1;}}return *this;
}Date Date::operator+(int day) {Date tmp = *this;tmp += day;//operator+=(int day)return tmp;
}bool Date::operator<(const Date& d) {if (_year > d._year) {return false;}if (_year < d._year) {return true;}if (_month > d._month) {return false;}if (_month < d._month) {return true;}if (_day >= d._day) {return false;}else {return true;}
}bool Date::operator>(const Date& d) {if (_year < d._year) {return false;}if (_year > d._year) {return true;}if (_month < d._month) {return false;}if (_month > d._month) {return true;}if (_day <= d._day) {return false;}else {return true;}}bool Date::operator>=(const Date& d) {if (_year < d._year) {return false;}if (_year > d._year) {return true;}if (_month < d._month) {return false;}if (_month > d._month) {return true;}if (_day < d._day) {return false;}else {return true;}}bool Date::operator<=(const Date& d) {if (_year > d._year) {return false;}if (_year < d._year) {return true;}//year相同if (_month > d._month) {return false;}if (_month < d._month) {return true;}//month相同if (_day >= d._day) {return false;}else {return true;}}bool Date::operator==(const Date& d) {return _year == d._year && _month == d._month && _day == d._day;}bool Date::operator!=(const Date& d) {Date tmp = *this;return !(tmp == d);}Date Date::operator-(int day) {Date tmp = *this;tmp -= day;return tmp;}Date& Date::operator-=(int day){//如果day为负号，则+=或者+if (day < 0){return *this += (-day);}//先减值_day -= day;while (_day <= 0){--_month;//防止month过0if (_month == 0){_month = 12;--_year;}//先-month是因为取天数，是在上个月中取，并非当前月_day += GetMonthDay(_year, _month);}return *this;}int Date::operator-(const Date& d) {int y1, m1, d1, y2, m2, d2;int arr[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };y1 = this->_year;m1 = this->_month;d1 = this->_day;y2 = d._year;m2 = d._month;d2 = d._day;int sum2 = 0;int sum1 = 0;if (y1 < y2) {swap(&y1, &y2);swap(&m1, &m2);swap(&d1, &d2);}if (y1 == y2) {if (m1 < m2) {swap(&m1, &m2);swap(&d1, &d2);}}if (y1 == y2) {if (m1 == m2) {if (d1 < d2) {swap(&d1, &d2);}}}//差的年数int x = y1 - y2;//记录2年的天数if (((y2 % 4 == 0) && (y2 % 100 != 0)) || y2 % 400 == 0) {//判断是否为闰年arr[1] = 29;}for (int i = 0; i < m2 - 1; i++) {sum2 += arr[i];}sum2 += d2;//记录1年的天数if (((y1 % 4 == 0) && (y1 % 100 != 0)) || y1 % 400 == 0) {//判断是否为闰年arr[1] = 29;}for (int i = 0; i < m1 - 1; i++) {sum1 += arr[i];}sum1 += d1;for (int i = 0; i < x; i++) {if (((y1 % 4 == 0) && (y1 % 100 != 0)) || y1 % 400 == 0) {sum1 += 366;}else {sum1 += 365;}}return sum1 - sum2;}Date::Date(const Date& d) {_year = d._year;_month = d._month;_day = d._day;}