Arithmetic/Integer: Difference between revisions

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 =={{header|Common Lisp}}==
-<lang lisp>(defun arithmetic ()
+<lang lisp>(defun arithmetic (&aux (a (read *query-io*)) (b (read *query-io*)))
+  (mapc
-  (let ((a (read *query-io*)) (b (read *query-io*)))
-    (format t "a + b = ~a~%" (+ a b))
+    (lambda (op &aux (form (list op a b)))
-    (format t "a - b = ~a~%" (- a b))
+      (format t "~a => ~a~%" form (eval form)))
-    (format t "a * b = ~a~%" (* a b))
+    '(+ - * mod rem floor ceiling truncate round expt)))</lang>
-    (format t "a / b = ~a~%" (/ a b))
+Common Lisp's integer division functions are <code>floor</code>, <code>ceiling</code>, <code>truncate</code>, and <code>round</code>. They differ in how they round their quotient.
-    (format t "a % b = ~a~%" (mod a b))))</lang>
+{| class="wikitable"
+! The function !! rounds its quotient towards
+|-
+! <code>floor</code>
+| negative infinity
+|-
+! <code>ceiling</code>
+| positive infinity
+|-
+! <code>truncate</code>
+| zero
+|-
+! <code>round</code>
+| the nearest integer (preferring the even integer if the mathematical quotient is equidistant from two integers)
+|}
+Each function also returns a remainder as its secondary value, such that
+  quotient * divisor + remainder = dividend .
+<code>(mod a b)</code> and <code>(rem a b)</code> return numbers equal to the secondary values of <code>(floor a b)</code> and <code>(truncate a b)</code>, respectively.
 =={{header|D}}==