日期类

#include<iostream>
using namespace std;
class Date
{
public:
    Date(int year=1970,int month=1,int day=1)//构造函数
        :_year(year)
        , _month(month)
        , _day(day)
    {
        if (!Check_Date())
        {
            cout << "非法日期！" << endl;
            exit(0);
        }
    }
    Date(const Date&d);//拷贝构造函数
    Date& operator=(const Date& d);//赋值运算符重载
    friend ostream& operator<<(ostream& _cout,Date& d);//输出流重载
    Date operator-(int days);//减去一个时间
    Date operator+(int days);//加上一个时间
    int operator-(const Date& d);//日期之间相差多少天
    //Date& operator++();//前置加加
    //Date operator++(int);//后置加加
    //Date& operator--();
    //Date operator--(int);
    bool operator>(const Date& d);
    bool operator<(const Date& d);
    bool operator==(const Date& d);
    bool operator!=(const Date& d);

    void Display();//显示日期
    int Month_day(int year,int month);//查看当前月有多少天
    bool Check_Date();//检查日期是否为合格日期
    bool  IsLeap()
    {
        if (((_year % 4 == 0) && (_year % 100 != 0)) || (_year % 400) == 0)
            return true;
        else
            return false;
    }
private:
    int _year;
    int _month;
    int _day;
};
int Date::Month_day(int year,int month)
{
    int DayOfMonth[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    if (((_year % 4 == 0) && (_year % 100 != 0)) || (_year % 400) == 0)
    {
        if (month == 2)
            return DayOfMonth[month] + 1;
        else
            return DayOfMonth[month];
    }
        else
            return DayOfMonth[month];

}
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;
}
ostream& operator<<(ostream& _cout, Date& d)
{
    _cout << d._year << "年" << d._month << "月" << d._day << "日";
    return _cout;
}
Date Date::operator-(int days)
{
    Date temp(*this);
    if (days>0)
    {
        temp._day = temp._day - days;
        while (temp._day<=0)
        {
            if (temp._month == 1)
            {
                temp._month = 12;
                temp._year -= 1;
            }
            else
                temp._month -= 1;
            temp._day =temp._day+ Month_day(temp._year, temp._month);
        }
    }
    else if (days<0)
    {
        return (*this) +(-days);
    }
    return temp;
}
int Date::operator-(const Date& d)
{
    int count = 0;
    Date FutureDate;
    Date PastDate;
    if (*this > d)
    {
        FutureDate=*this;
        PastDate=d;
    }
    else
    {
        FutureDate = d;
        PastDate =*this;
    }
    while (FutureDate != PastDate)
    {
        PastDate = PastDate+1;
        count++;
    }
    return count;
}
bool Date::operator>(const Date&d)
{
    if ((_year <= d._year) && (_month <= d._month) && (_day <= d._day))
        return false;
    else
    {
        if ((_year == d._year) && (_month == d._month) && (_day == d._day))
            return false;
            return true;
    }
}
bool Date::operator<(const Date&d)
{
    if ((_year >= d._year) && (_month >= d._month) && (_day >= d._day))
        return false;
    else
    {
        if ((_year == d._year) && (_month == d._month) && (_day == d._day))
            return false;
        return true;
    }
}
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 ((_year == d._year) && (_month == d._month) && (_day == d._day))
        return false;
    else
        return true;
}
Date Date::operator+(int days)
{
    Date temp(*this);
    if (days < 0)
    {
        return *this - (-days);
    }
    else if (days>=0)
    {
        temp._day = temp._day + days;
        while (temp._day>Month_day(temp._year, temp._month))
        {
            temp._day = temp._day - Month_day(temp._year, temp._month);
            if (temp._month == 12)
            {
                temp._month = 1;
                temp._year += 1;
            }
            else
                temp._month += 1;
        }
    }
    return temp;
}
bool Date::Check_Date()
{
    if (_year > 0)
    {
        if (_month > 0 && _month <= 12)
        {
            if (_day > 0 && (_day <= Month_day(_year,_month)))
                return true;
        }
    }
    return false;
}
void Date::Display()
{
    cout << _year << "年" << _month << "月" << _day << "日" << endl;
}
int main()
{
    Date d1(2017, 4, 26);
    Date d2;
    Date d3(2016,4,26);
    //Date d2(1000, 2, 11);
    //int ret = d1.Month_day();
    //cout << ret<<endl;
     d2 = d1;
    /*d1.Display();
    d2.Display();
    d3.Display();*/
    /*cout << d1<<endl;
    d3 = d1 + 999;
    cout << d3 << endl;*/
     int count = d3 - d1;
     cout << count;
    return 0;
}