Small Flows

(defun print-prime-number (&key (begin 2) (end 100)) (format t "prime number between ~d and ~d: " begin end) (format t "~{~d~t~}" (loop for i from begin to end when (loop for j from 2

相等运算符： 1. =，char= 2. eq，eql 3. equal, equalp

;;;; print 12 months accroding index in a week ;; if year is leap year? (defun is-leap-year (year) (or (and (= 0 (mod year 4)) (/= 0 (mod year 100))) (= 0 (mod year 400)))) ;; retu