2017.04.21
Checking whether an input element is a number or not with using DO macro. (Infinite Loop)
(defun read-a-number () (do ((answer nil)) (nil) ; This is necessary to make Infinite Loop function. (format t "~&Please type a number: ") (setf answer (read)) (if (numberp answer) (return answer) (format t t "~&Sorry, ~S is not a number. Try again." answer)))) A Program which checks whether the input number is a number or not by using DO macro. If the input number is not a number, the program p..