C++日期计算器的实现

#include<iostream>
using namespace std;

class Date
{
friend void print_date(int year, int month);//打印日历
friend ostream& operator<<(ostream&_cout, const Date& d);
friend istream& operator>>(istream&_cin, Date& d);

public:
int days_aimmonth(int year, int month);//所求月的天数
int week_firstday(int year, int month);//统计目标月份第一天是周几
Date();
Date(int year, int month, int day);
Date(const Date&d);
Date& operator=(const Date& d);
Date& operator+(int day);
Date& operator++(int);
Date& operator++();
Date& operator--();
Date& operator--(int);
int operator-(Date& d);
Date& operator-(int day);

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);

private:
int _year;
int _month;
int _day;
};

bool Judge_leap(int year);//判断是否为闰年
static int week_firstday(int year, int month);

#include "test.h"
ostream& operator<<(ostream&_cout, const Date& d)
{
_cout << d._year << "-" << d._month << "-" << d._day;
return _cout;
}

istream& operator>>(istream&_cin, Date& d)
{
_cin >> d._year >> d._month >> d._day;
return _cin;
}

Date::Date()
{}

Date::Date(int year = 2017, int month = 1, int day = 1)
:_year(year), _month(month), _day(day)
{
if (day > days_aimmonth(_year,_month))
{
_day = day - days_aimmonth(_year, _month);
_month += 1;

if (month > 12)
{
_month -= 12;
_year += 1;
}
}
}

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

Date& Date::operator=(const Date &d)
{
if (*this != d)
{

_year = d._year;
_month = d._month;
_day = d._day;
}
return *this;
}

Date& Date::operator+(int day)
{
_day = _day + day;

while (_day > days_aimmonth(_year, _month))
{
_day = _day - days_aimmonth(_year, _month);
_month += 1;

if (_month > 12)
{
_year += 1;
_month = 1;
}
}
return *this;
}

Date& Date::operator++(int)
{
++_day;
if (_day > days_aimmonth(_year, _month))
{
_day = _day - days_aimmonth(_year, _month);
_month += 1;
if (_month > 12)
{
_year+=1;
_month -= 12;
}
}
return *this;
}

Date& Date::operator++()
{
_day++;
if (_day > days_aimmonth(_year, _month))
{

_day = _day - days_aimmonth(_year, _month);
_month += 1;
if (_month > 12)
{
_year += 1;
_month -= 12;
}
}
return *this;
}

Date& Date::operator-(int day)
{
_day = _day - day;
while (_day <= 0)
{
_day += days_aimmonth(_year, _month);
_month -= 1;
if (_month <= 0)
{
_year -= 1;
_month = 12;
}
}
return *this;
}

int Date::operator-(Date& d) //日期减日期
{
Date min(*this);
Date max(d);
int tag = -1;
int count = 0;
if (d < *this)
{
min = d;
max = *this;
tag = 1;
}
while (min != max)
{
++min;
count++;
}
return tag*count;
}

Date& Date::operator--()
{
_day--;
if (_day == 0)
{
_day = days_aimmonth(_year, _month);
_month -= 1;
if (_month == 0)
{
_year -= 1;
_month = 12;
}
}
return *this;
}

Date& Date::operator--(int)
{
--_day;
if (_day == 0)
{
_day = days_aimmonth(_year, _month);
_month -= 1;
if (_month == 0)
{
_year -= 1;
_month = 12;
}
}
return *this;
}

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;
}
}
}
return false;
}

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

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

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

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

bool Date::operator!=(const Date d)
{
if (*this == d)
return false;
else
return true;
}

void print_date(int year, int month)//打印目标月份日历
{
cout << year << "年" << month << "月" << endl;
cout << "日 " << "一 " << "二 " << "三 " << "四 " << "五 " << "六 " << endl;
int i = 0;
int j = 0;
Date temp(year, month, 1);
int week = week_firstday(year, month);
int day = temp.days_aimmonth(year, month);
int k = 1;

for (i = 0; i < week; i++)
{
cout << "   ";
}
for (i = 0; i < 6; i++)
{
for (j = 0; j < 7; j++)
{
if (i == 0)
{
if (j == 7 - week)
break;
}
if (k <= day)
printf("%2d ", k++);
}
cout << endl;
}
}

static bool Judge_leap(int year)//判断是否为闰年
{
if ((year % 4 == 0) || (year % 400 == 0) && (year % 100 != 0))
return true;
else
return false;
}

int Date::days_aimmonth(int year, int month)//求目标月份天数
{
int day[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
if (Judge_leap(year) == true)
{
day[2] = 29;
}
return day[month];
}

static int week_firstday(int year, int month)
{
Date d1(1949, 9, 1);//新中国自1949年开始使用公元纪年法
int week = 4;//公元1949年9月1日为周四
int day = 0;
Date d2(year, month, 1);
day = d2 - d1;
week += day % 7;
if (week > 7)
{
week -= 7;
}
return week;
}

#include "test.h"

void menu()
{
cout << "####  ---请输入想进行的运算的序号---  ####" << endl;
cout << "#### 1.打印目标月份日历（格式：年 月）####" << endl;
cout << "#### 2.相隔天数计算  #####################" << endl;
cout << "#### 3.日期推算(填负数向前推进) ##########" << endl;
cout << "#### 0.退出###############################" << endl;

}

int main()
{
menu();
while (1)
{
int num = 0;
cin >> num;

switch (num)
{
case 1:
{
cout << "请输入年份月份:";
int a = 0, b = 0;
cin >> a;
cin >> b;
print_date(a, b);
break;
}
case 2:
{
cout << "请输入日期：";
Date d1;
cin >> d1 ;

cout << "请输入日期：";
Date d2;
cin >> d2;

int day = 0;
day = d1 - d2;
cout <<"日期相差："<< day <<"天"<< endl;
break;
}

case 3:
{
cout << "请输入日期：";
Date d1,d2;
cin >> d1;

cout << "请输入推算的天数：";
int n = 0;
cin >> n;

cout << "推算后日期为：";
if (n > 0)
{
d2 = d1 + n;
}
else
{
d2 = d1 - (-n);
}
cout<<d2;
break;
}
case 0:
return 0;
}
}

system("pause");
return 0;
}