代入参数年y,月m,日d 即可返回所得的星期
public static string getWeekDay(int y, int m, int d)
{
if(m==1) {m=13;y--;}if(m==2) {m=14;y--;}
int week = (d + 2 * m + 3 * (m + 1) / 5 + y + y / 4 - y / 100 + y/400) % 7 + 1;
string strweek=""; switch (week)
{
case 1: strweek = "星期一"; break; case 2: strweek = "星期二"; break; case 3: strweek = "星期三"; break; case 4: strweek = "星期四"; break; case 5: strweek = "星期五"; break; case 6: strweek = "星期六"; break; case 7: strweek = "星期日"; break;
} return strweek;
}