Day of the Week

This program computes the day of the week for any date since September 14, 1752 .*

The calculator displays the day of the week as an integer from 0 to 6 with the following correspondence:

0 Sunday
1 Monday
2 Tuesday
3 Wednesday
4 Thursday
5 Friday
6 Saturday


* September 14, 1752 is the date that England and its colonies switched from the Julian Calendar to the current Gregorian Calendar. At that time eleven days were suppressed interrupting the continuity of the calendar. The suppression was necessary since the Julian Calendar was falling behind by 3 days every 400 years. This problem is corrected in the Gregorian Calendar by eliminating 3 leap years every 400 years. In the Gregorian system, century years (1700, 1800, 1900, etc.) are not leap years unless they are divisible by 400 (2000, 2400, 2800, etc.)


Example 1: Von Ohain made the first jet powered flight on August 27, 1939. What was the day of the week?

8 A
27 B
1939 C
0.00 (Sunday)


Example 2: After completing 492 deep soundings, taking 263 water temperature observations, dredging for 133 bottom samples, trawling 151 times and covering 68,890 nautical miles, the H.M.S. Challenger returned to England on May 24 1876. The most important voyage in the history of oceanography was over.
What was the day of the week?

5 A
24 B
1876 C
3.00 (Wednesday)