Lesson 5

Hamled · Apr 6, 2019 · abcd3f6 · abcd3f6
1 parent 1af1542
commit abcd3f6
Showing 1 changed file with 19 additions and 0 deletions.
diff --git a/lesson-5/contracts.rkt b/lesson-5/contracts.rkt
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+#lang racket
+
+(define/contract (f x)
+  (exact-integer? . -> . exact-integer?)
+  (* x (add1 x)))
+
+(define (infinite? n)
+  (or (= +inf.0)
+      (= +inf.f)
+      (= -inf.0)
+      (= -inf.f)))
+
+(define/contract (cool x y)
+  (real? real? . -> . (or/c exact-integer?
+                            infinite?))
+  (define m (max (ceiling x) (ceiling y)))
+  (if (infinite? m)
+      m
+      (f (inexact->exact m))))