# Is it a leap year

Here's a bit of elisp code to find out...

(defun is-century-year(year)

(if (= (mod year 100) 0)

t

nil))

(defun is-leap-year(year)

"leap year is century years divisible by 400,

not other century years, otherwise anything evenly

divisble by 4"

(if (is-century-year year)

(if (= 0 (mod year 400))

t

nil)

(if (= 0 (mod year 4))

t

nil)))