A-M baby

Task/Gray-code/Scala/gray-code-1.scala

@@ -0,0 +1,6 @@
+def encode(n: Int)    = (n ^ (n >>> 1)).toBinaryString
+def decode(s: String) = Integer.parseInt( s.scanLeft(0)(_ ^ _.asDigit).tail.mkString , 2)
+
+println("decimal  binary   gray  decoded")
+for (i <- 0 to 31; g = encode(i))
+  println("%7d  %6s  %5s  %7s".format(i, i.toBinaryString, g, decode(g)))

Task/Gray-code/Scala/gray-code-2.scala

@@ -0,0 +1,19 @@
+def encode(n: Long) = n ^ (n >>> 1)
+
+def decode(n: Long) = {
+  var g = 0L
+  var bits = n
+  while (bits > 0) {
+    g ^= bits
+    bits >>= 1
+  }
+  g
+}
+
+def toBin(n: Long) = ("0000" + n.toBinaryString) takeRight 5
+
+println("decimal  binary   gray  decoded")
+for (i <- 0 until 32) {
+  val g = encode(i)
+  println("%7d  %6s  %5s  %7s".format(i, toBin(i), toBin(g), decode(g)))
+}

Task/Gray-code/Scala/gray-code-3.scala

@@ -0,0 +1,4 @@
+def decode(n:Long)={
+  def calc(g:Long,bits:Long):Long=if (bits>0) calc(g^bits, bits>>1) else g
+  calc(0, n)
+}