From: Ramakrishnan Muthukrishnan <vu3rdd@gmail.com>
Date: Mon, 21 Jun 2010 14:09:57 +0000 (+0530)
Subject: solution to 2.20
X-Git-Url: https://git.rkrishnan.org/simplejson/components/frontends/statistics?a=commitdiff_plain;h=3bba508f6af3423f20e044562183bc40f3cc5087;p=sicp.git

solution to 2.20
---

diff --git a/src/sicp/ex2_20.clj b/src/sicp/ex2_20.clj
new file mode 100644
index 0000000..24b5f5e
--- /dev/null
+++ b/src/sicp/ex2_20.clj
@@ -0,0 +1,16 @@
+(ns sicp.ex2_20
+  (:use [clojure test]
+	[sicp utils]))
+;; clojure has a slightly different notation compared to Scheme for the
+;; arbitraty number of argument notation.
+(defn same-parity [x & xs]
+  (cons x (filter (fn [y] (if (even? x)
+			    (even? y)
+			    (odd? y)))
+		  xs)))
+
+(deftest test-same-parity
+  (are [x y] [= x y]
+       (same-parity 1 2 3 4 5 6 7) (list 1 3 5 7)
+       (same-parity 2 3 4 5 6 7) (list 2 4 6)))
+