From b213cfec8252a9c803964ba5b9f9dd2107aebfbd Mon Sep 17 00:00:00 2001
From: Natalia Kuleniuk <bilberryfm@mail.ru>
Date: Mon, 27 Mar 2017 20:54:16 -0700
Subject: [PATCH] recursion writing exercise

---
 recursion-writing.rb | 54 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 recursion-writing.rb

diff --git a/recursion-writing.rb b/recursion-writing.rb
new file mode 100644
index 0000000..5856512
--- /dev/null
+++ b/recursion-writing.rb
@@ -0,0 +1,54 @@
+def factorial(n)
+  if n == 0
+    return n
+  else
+    return n * factorial(n-1)
+  end
+end
+
+def reverse(s)
+  if s.length == 1
+    return s
+  else
+    return s[-1] + reverse(s[0...-1])
+  end
+end
+
+def bunny(n)
+  if n == 0
+    return 0
+  else
+    return 2 + bunny(n-1)
+
+  end
+end
+
+def nested(s)
+  if s.length % 2 != 0
+    return false
+  elsif s.length == 0
+    return true
+  elsif s[0] == "(" && s[-1] == ")"
+    return nested(s[1...-1])
+  else
+    return false
+  end
+end
+
+def fib(n)
+  if n == 1 || n == 0
+    return n
+  else
+    return fib(n-1) + fib(n-2)
+  end
+end
+
+def pal(s)
+  if s.length <= 1
+    return true
+  elsif s[0] == s[-1]
+    return pal(s[1...-1])
+  else
+    return false
+  end
+end