一個挺不可思議的程序

//year:00-99
//month:01-12
//day:01-31
unsignedcharGetWeekFromDay(unsignedcharyear,unsignedcharmonth,unsignedcharday)
{
if(month==1||month==2)
{
month+=12;
if(year>0)
year--;
else
year=4;
}

//返回星期幾(星期一用1表示，而星期天用7表示)
return1+((day+2*month+3*(month+1)/5+year+year/4)%7);
}