C++當前日期加1天

#include<iostream>
using namespace std;

class Date
{
private:
	int year;
	int month;
	int day;

public:
	Date(){}
	Date(int y,int m,int d)
	{
		year=y;
		month=m;
		day=d;
	}
	Date NextDay();
	void Show()
	{
		cout<<year<<"-"<<month<<"-"<<day<<endl;
	}
private:
    bool IsLeapYear();
};
Date Date::NextDay()
{
	Date t;
	t.day=day;
	t.month=month;
	t.year=year;
	t.day++;
    if(IsLeapYear())    
    {
        if(t.month == 2 && day == 30)
        {
            t.day = 1;
            t.month++;
        }
    }
    else            //???
    {
        if(t.month == 2 && t.day == 29)
        {
            t.day=1;
            t.month++;
        }
    }
    if(t.day > 31)
    {
        if(t.month == 12)
        {
            t.day = 1;
            t.month = 1;
            t.year++;
        }
        else
        {
            t.day = 1;
            t.month++;
        }
    }
    else if(t.day == 31)
    {
        if(t.month==4||t.month==6||t.month==9||t.month==11)  
        {
            t.day=1;
            t.month++;
        }
    }
	return t;
}
bool Date::IsLeapYear()    
{
	bool bleap;
    if((year%4 == 0 && year%100 != 0) || year%400 == 0)
        bleap = true;
    else
        bleap = false;
    return bleap;
}
int main()
{
	int y,m,d;
	cout<<"printf the date:"<<endl;
	scanf("%d%d%d",&y,&m,&d);
	Date d1(y,m,d);
	Date d2;
	d2=d1.NextDay();
	d2.Show();
	system("pause");
	return 0;
}