A-M baby

Task/Gray-code/Ruby/gray-code.rb

@@ -0,0 +1,26 @@
+class Integer
+  # Converts a normal integer to a Gray code.
+  def to_gray
+    raise Math::DomainError, "integer is negative" if self < 0
+    self ^ (self >> 1)
+  end
+
+  # Converts a Gray code to a normal integer.
+  def from_gray
+    raise Math::DomainError, "integer is negative" if self < 0
+    recurse = proc do |i|
+      next 0 if i == 0
+      o = recurse[i >> 1] << 1
+      o | (i[0] ^ o[1])
+    end
+    recurse[self]
+  end
+end
+
+
+(0..31).each do |number|
+  encoded = number.to_gray
+  decoded = encoded.from_gray
+  printf("%2d: %5b => %5b => %5b: %2d\n",
+         number, number, encoded, decoded, decoded)
+end