Day of Week -- A program for converting Gregorian dates in the form month-day-year to day of the

week is the following. Let the Gregorian date be represented by M/D/Y where we have the following

definitions:

M is the month of the year. Let m be the month number derived from M by the rule m is M-2

if M>=3 and m is M + 10 otherwise.

d is the day of the month.

y is the year of the century.

c is the number of the previous century.

The algorithm is as follows:

(a) A is the integer part of (13m - 1)/5.

(b) B is the integer part of y/4.

(c) C is the integer part of c/4.

(d) D = A + B + C + d + y - 2c.

(e) Make R equal to the remainder of D/7.

(f) Interpret R as Sunday if R = 0, Monday if R is 1, etc.