任意年.c

星期算法,即知道日期,即可知道该天是星期几

#include <stdio.h>
#define uchar unsigned char
#define uint  unsigned int

uchar week(uint year,uchar month,uchar day);
code uchar WEEK_BIAO_P[]={4,0,0,3,5,1,3,6,2,4,0,2};	//平年月星期表
code uchar WEEK_BIAO_R[]={3,6,0,3,5,1,3,6,2,4,0,2};     //闰年月星期表
void main(void)
{
	uchar a;
	uchar month,day;
	uint year;
	year=2004;month=6;day=9;
	while(1)
	{
	  a=week(year,month,day);
	 }
}




/*********************************************************************
  将2004年代入。得(其中百年=20，年=04)
  2004某日星期几=(百年%4*5天+年+年/4+月星期表+日+2天)%7
  入口参数:year(年),month(月),day(日)
  出口参数:return_week(星期几)
  影响变量:无
  调用函数:无
  占用空间:6个单元RAM
*********************************************************************8*/
uchar week(uint year,uchar month,uchar day)
{
   uchar return_week;  
   uchar centry;
   centry=year/100;
   year=year%100;
   //if(
   return_week=( centry%4*5 + year +year/4 +WEEK_BIAO_P[month-1] + day +2 )%7;
   return return_week;
}