easter.csh easter.cshPrevious | Next

 # Calculate when Easter will occur in any given year. # Copyright (c) 1991-2012 by Hamilton Laboratories. All rights reserved. proc easter (year) local a, b, c, d, e, f, g, h, i, k, l, m, n, month, day set month = January February March April May June ^ July August September October November December if (year == "") @ year = `date`:3 if (year >= 1583) then # Gregorian calendar @ a = year % 19; @ b = year // 100; @ c = year % 100 @ d = b // 4; @ e = b % 4; @ f = (b + 8) // 25 @ g = (b - f + 1) // 3 @ h = (19 * a + b - d - g + 15) % 30 @ i = c // 4; @ k = c % 4 @ l = (32 + 2 * e + 2 * i - h - k) % 7 @ m = (a + 11 * h + 22 * l) // 451 @ n = h + l - 7 * m + 114 @ month = month[n // 31 - 1] @ day = n % 31 + 1 else # Julian calendar @ a = year % 4; @ b = year % 7; @ c = year % 19; @ d = (19 * c + 15) % 30 @ e = (2 * a + 4 * b - d + 34) % 7 @ f = d + e + 114 @ month = month[f // 31 - 1] @ day = f % 31 + 1 end return "\$month \$day \$year" end easter \$argv