【C++】基础类之日期类

1. DateClass.h2. DateClass.cpp3. Text.cpp

1. DateClass.h

<code>#pragma once

#include<iostream>

#include<assert.h>

using namespace std;

class Date

{ -- -->

public:

Date(int year, int month, int day);

Date(const Date& date)

{

_year = date._year;

_month = date._month;

_day = date._day;

}

void Print()

{

cout << "year:" << _year << "month:" << _month << "day:" << _day << endl;

}

//得到对应year（平年或瑞年）对应month的天数

int GetMonthDay(int year, int month);

//两日期比较

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;

//日期加天数，“+=”与“+”的区别在于是否改变当前日期本身

Date& operator+=(const int day);//改变

Date operator+(const int day)const;//不改变

//日期减天数，同上

Date& operator-=(const int day);

Date operator-(const int day)const;

//前后置++，改变当前日期本身

Date& operator++();//const Date& operator++();

Date operator++(int);

//前后置--，改变当前日期本身

Date& operator--();

Date operator--(int);

//两日期间隔天数

int operator-(const Date& date)const;

//日期赋值

Date& operator=(const Date& date);

// 流插入不能写成成员函数?

// 因为Date对象默认占用第一个参数，就是做了左操作数

// 写出来就一定是下面这样子，不符合使用习惯

//d1 << cout; // d1.operator<<(cout);

//void operator<<(ostream& out);

/*int GetYear()

{

return _year;

}*/

friend ostream& operator<<(ostream& out, const Date& date);

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

private:

int _year = 0;

int _month = 0;

int _day = 0;

};

ostream& operator<<(ostream& out, const Date& date);

istream& operator>>(istream& in, Date& date);

2. DateClass.cpp

#include"DateClass.h"

int Date::GetMonthDay(int year, int month)

{

static int daysArr[13] = { 0,31,28,31,30,31,30,31,31,30,31,30 };

if (month == 2 && ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0))

{

return 29;

}

else

return daysArr[month];

}

Date::Date(int year, int month, int day)

{

if (month > 0 && month < 13 && day < GetMonthDay(year, month))

{

_year = year;

_month = month;

_day = day;

}

else

{

cout << "非法日期" << endl;

assert(false);

}

}

bool Date::operator>(const Date& d)const

{

if (_year > d._year)

{

return true;

}

if (_year == d._year && _month > d._month)

{

return true;

}

if (_year == d._year && _month == d._month && _day > d._day)

{

return true;

}

return false;

}

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 || *this == d);

}

bool Date::operator>=(const Date& d)const

{

return *this > d || *this == d;

}

bool Date::operator<=(const Date& d)const

{

return !(*this > d);

}

bool Date::operator!=(const Date& d)const

{

return !(*this == d);

}

Date& Date::operator+=(const 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+(const int day)const

{

Date tmp = *this;

tmp += day;

return tmp;

}

Date& Date::operator-=(const int day)

{

if (day < 0)

{

return *this += -day;

}

_day -= day;

while(_day <= 0)

{

_month--;

if (_month == 0)

{

_year--;

_month = 0;

}

_day += GetMonthDay(_year, _month);

}

return *this;

}

Date Date::operator-(const int day)const

{

Date tmp = *this;

tmp -= day;

return tmp;

}

//const Date& Date::operator++()

//{

//return *this + 1;

//}

Date& Date::operator++()

{

*this += 1;

return *this;

}

Date Date::operator++(int)

{

Date tmp = *this;

*this += 1;

return tmp;

}

Date& Date::operator--()

{

*this -= 1;

return *this;

}

Date Date::operator--(int)

{

Date tmp = *this;

*this -= 1;

return tmp;

}

int Date::operator-(const Date& date)const

{

Date max = *this;

Date min = date;

int flag = 1;

if (*this < date)

{

max = date;

min = *this;

flag = -1;

}

int count = 0;

while (min != max)

{

min++;

count++;

}

return count * flag;

}

Date& Date::operator=(const Date& date)

{

if (this != &date)//注意用地址比较

{

_year = date._year;

_month = date._month;

_day = date._day;

}

return *this;

}

ostream& operator<<(ostream& out, const Date& date)

{

out << "year:" << date._year << "month:" << date._month << "day:" << date._day << endl;

return out;

}

istream& operator>>(istream& in, Date& date)

{

int year, month, day;

in >> year >> month >> day;

if (month > 0 && month < 13

&& day > 0 && day <= date.GetMonthDay(year, month))

{

date._year = year;

date._month = month;

date._day = day;

}

else

{

perror("非法日期");

assert(false);

}

return in;

}

3. Text.cpp

#include"DateClass.h"

void Text1()

{

Date d1(2024, 6, 26);

Date d2(2024, 6, 21);

cout << (d1 < d2) << endl; // 转换成cout << operator<(d1, d2);

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

cout << (d1 < d2) << endl; // 转换成cout << d1.operator<(d2);

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

}

void Text2()

{

Date d1(2024, 6, 26);

Date d2(2024, 6, 21);

cout << (d1 += 1);//此时输出:2024,6,27,d1被改变

cout << (d1 + 1);//此时输出:2024,6,28，d1未被改变

cout << (d1 -= 1);

cout << d1++;

cout << ++d1;

int gap = (d2 - d1);

cout << gap;

}

void Text3()

{

Date d1(2024, 6, 26);

Date d2(2024, 6, 21);

// 已经存在的两个对象之间复制拷贝 -- 运算符重载函数

d1 = d2;

cout << d1;

// 用一个已经存在的对象初始化另一个对象 -- 构造函数

Date d3(d1);

}

int main()

{

//Text1();

//Text2();

Text3();

return 0;

}