生日问题.cpp

生日是星期几 写一个程序

#include<iostream.h>
struct Date
{
	int month;
	int day;
	int year;
};
class datetype
{
public:
	    datetype(Date b);
	    void modify(int m,int d,int y);
	    void tomorrow();
	    void previous();
	    int weekday();
	    void print();
protected:
	    Date a;
	    int isleapyear();
	    int monthend(int m);
};
datetype::datetype(Date b)
{
	a.month=b.month;
	a.day=b.day;
	a.year=b.year;
}
void datetype::modify(int m,int d,int y)
{
	a.month=m;
	a.month=d;
	a.month=y;
}
void datetype::tomorrow()
{
	a.day++;
	if(a.day>monthend(a.month))
	{
		a.day=1;
		a.month++;
		if(a.month>12)
		{
			a.month=1;
			a.year++;
		}
	}
}
void datetype::previous()
{
	a.day--;
	if(a.day<1)
	{
		a.month--;
		if(a.month<1)
		{
			a.month=12;
			a.year--;
		}
		a.day=monthend(a.month);
	}
}
int datetype::isleapyear()
{
	return((a.year%4==0 && a.year%100!=0)||(a.year%400==0));
}
int datetype::monthend(int m)
{
	switch(m)
	{
	    case 1:
	    case 3:
	    case 5:
	    case 7:
	    case 8:
	    case 10:
	    case 12: return 31;
	    case 4:
	    case 6:
	    case 9:
	    case 11: return 30;
	    case 2:
		    if(isleapyear())
			    return 29;
		    else
			    return 28;
	}
	return 0;
}
int datetype::weekday()
{
	long n;
	n=(a.year-1)*365;
	n+=(a.year-1)/4;
	n-=(a.year-1)/100;
	n+=(a.year-1)/400;
	for(int i=1;i<a.month;i++)
		n+=monthend(i);
    n+=a.day;
	n%=7;
	return n;
}
void datetype::print()
{
	cout<<a.year<<'年'<<a.month<<'月'<<a.day<<'日'<<endl;
	switch(weekday())
	{
	    case 0:cout<<"Sun\n";  break;
	    case 1:cout<<"Mon\n";  break;
	    case 2:cout<<"tue\n";  break;
	    case 3:cout<<"wed\n";  break;
	    case 4:cout<<"thu\n";  break;
	    case 5:cout<<"fri\n";  break;
	    case 6:cout<<"sat\n";  break;
	}
}
void main()
{
	Date a={4,22,1999};
	datetype oneday(a);
	oneday.print();
	oneday.tomorrow();
	oneday.print();
    oneday.modify(2,15,1999);
	oneday.print();
    oneday.previous();
	oneday.print();
}