【C++】实现万年历

<span style="font-size:18px;">/******************************************************************************************
Purpose:
声明并实现一个万年历类【腾讯面试题】

Author:
周蒙蒙

Created Time:
2015-8-19
******************************************************************************************/
#include<iostream>
using namespace std;

class Date
{
public:
// 初始化列表进行初始化。
//带缺省值的构造函数
Date(int year = 1900, int month = 1, int day = 1)
:_year(year),
_month(month),
_day(day)
{
if (CheakDate()==0)
{
_year = 1900;
_month = 1;
_day = 1;
}
}
//检查日期是否合法
bool CheakDate()
{
if ((_year < 1) || (_month<0) || (_month)>12 || (_day)<0 || (_day)>GetMonthDay(_year, _month))
{
cout << "invaled date" << endl;
return 0;
}
return 1;
}
//拷贝构造函数
Date(const Date& d)
: _year(d._year),
_month(d._month),
_day(d._day)
{}
//赋值操作符的重载
Date& operator= (const Date& d)
{
if (*this != d)
{
_year = d._year;
_month = d._month;
_day = d._day;
}
return *this;
}
void Display()
{
cout << _year << "-" << _month << "-" << _day << endl;
}
public:
// 比较日期的运算符重载
// 借鉴代码的复用
bool operator == (const Date& d)
{
return _year == d._year &&
_month == d._month &&
_day == d._day;

}
bool operator != (const Date& d)
{
return !(*this == d);
}
bool operator > (const Date& d)
{
if (_year > d._year)
{
return 1;
}
if (_year == d._year)
{
if (_month > d._month)
{
return 1;
}
if (_month == d._month)
{
if (_day > d._day)
{
return 1;
}
if (_day == d._day)
{
return 0;
}
}
}
return 0;
}
bool operator >= (const Date& d)
{
return ((*this > d) || (*this == d));
}
bool operator < (const Date& d)
{
return !(*this >= d);
}
bool operator <= (const Date& d)
{
return !(*this>d);
}
//判断是否是闰年
static int Leap_Year(int year)
{
if ((year % 400 == 0) || ((year % 4 == 0) && (year % 100 != 0)))
return 1;
else
return 0;
}
//用数组比switch case 语句更简洁
static int GetMonthDay(int year, int month)
{
static int Months[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
if (Leap_Year(year) == 1)
{
Months[2] = 29;
}
else
{
Months[2] = 28;
}
return Months[month];
}
// 计算一个日期加减一个天数以后的日期。注意：加的天数有可能是负数
Date operator+(int day)
{
Date d(*this);
d._day += day;
while (d._day<0)
{
if (d._month == 1)
{
d._year--;
d._month = 12;
}
else
{
d._month--;
}
d._day += GetMonthDay(d._year, d._month);
}
while (d._day > GetMonthDay(d._year, d._month))
{
d._day -= GetMonthDay(d._year, d._month);
if (d._month == 12)
{
d._year++;
d._month = 1;
}
else
{
d._month++;
}
}
return d;
}
Date operator-(int day)
{
Date d(*this);
if (day < 0)
{
day = 0 - day;
return *this + day;
}
d._day -= day;
if (d._day < 0)
{
while (d._day<0)
{
if (d._month == 1)
{
d._year--;
d._month = 12;
}
else
{
d._month--;
}
d._day += GetMonthDay(d._year, d._month);
}
}
return d;
}
Date& operator-=(int day)
{
(*this) = (*this - day);
return *this;
}
Date& operator+=(int day)
{
(*this) = (*this + day);
return *this;
}

const Date& operator++()// 前置++
{
(*this) = (*this + 1);
return *this;
}
Date operator++(int)		// 后置++
{
Date tmp(*this);
(*this) = (*this + 1);
return tmp;
}
const Date& operator--()	// 前置--
{
(*this) = (*this - 1);
return *this;
}
Date operator--(int)		// 后置--
{
Date tmp(*this);
(*this) = (*this - 1);
return tmp;
}

// 两个日期相加没有意义
// 计算两个日期相减以后的差的天数
int operator-(const Date& d)
{
Date d1(*this);
Date d2(d);
if (d1 > d2)
{
d1 = d;
d2 = *this;
}
int count = 0;
while (d1 != d2)
{
d1++;
++count;
}
return count;
}
friend istream& operator>>(istream& is, Date& d);
friend ostream& operator<<(ostream& os, Date& d);
private:
int _year;
int _month;
int _day;

};
//输入运算符的重载
istream& operator>>(istream& is, Date& d)
{
cout << "请依次输入年-月-日" << endl;
is >> d._year;
is >> d._month;
is >> d._day;
return is;
}
//输出运算符的重载
ostream& operator<<(ostream& os, Date& d)
{
os << d._year << "-";
os << d._month << "-";
os << d._day;
return os;
}
void PromptInfo()
{
cout << "|**********日期计算器************|"<<endl;
cout << "|********1.退后几天的日期 *******|"<< endl;
cout << "|********2.计算日期差************|" << endl;
cout << "|********0.退出******************|" << endl;
cout << "|********************************|" << endl;
}

int main()
{
Date d1, d2;
while (1)
{
PromptInfo();
int in = 0, day = 0;
cout << "请选择:" << endl;
cin >> in;
switch (in)
{
case 0:
cout << "Exit!" << endl;
return 0;
case 1:
cin >> d1;
if (d1.CheakDate()==0)
{
cout << "非法日期，请重新输入!" << endl;
break;
}
cout << "请输入退后的天数" << endl;
cin >> day;
cout << d1 + day << endl;
break;
case 2:
cin >> d1;
if (d1.CheakDate()==0)
{
cout << "非法日期，请重新输入!" << endl;
break;
}
cin >> d2;
if (d2.CheakDate()==0)
{
cout << "非法日期，请重新输入!" << endl;
break;
}
cout << d1 - d2 << endl;
break;
default:
cout << "输入选项错误，请重新输入!" << endl;
}
}
return 0;
}</span>