Hi, Any one out there have C example code on daylight saving time.? I already have r/w date_Time(), two date_compare() routines based on dallas DS1302. Thanks.
The magic Google phrase for calculating the day of the week is "Zeller's Congruence". http://www.lysator.liu.se/faq/c-faq/c-17.html#17-28
dayofweek(y, m, d) /* 0 = Sunday */ int y, m, d; /* 1 <= m <= 12, y > 1752 or so */ { static int t[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4}; y -= m < 3; return (y + y/4 - y/100 + y/400 + t[m-1] + d) % 7; }
Thanks Drew for the code.