Arduino Days of Week

void daysofweek()
{
int d    = 6;         //Day     1-31
int m    = 9;       //Month   1-12
int y    = 1982;     //Year    1982

int weekdays  = (d += m < 3 ? y-- : y - 2, 23*m/9 + d + 4 + y/4- y/100 + y/400)%7;
Serial.println(weekdays);
}