langs a-z

Task/Gray-code/OCaml/gray-code.ocaml

@@ -0,0 +1,26 @@
+let gray_encode b =
+  b lxor (b lsr 1)
+
+let gray_decode n =
+  let rec aux p n =
+    if n = 0 then p
+    else aux (p lxor n) (n lsr 1)
+  in
+  aux n (n lsr 1)
+
+let bool_string len n =
+  let s = String.make len '0' in
+  let rec aux i n =
+    if n land 1 = 1 then s.[i] <- '1';
+    if i <= 0 then s
+    else aux (pred i) (n lsr 1)
+  in
+  aux (pred len) n
+
+let () =
+  let s = bool_string 5 in
+  for i = 0 to pred 32 do
+    let g = gray_encode i in
+    let b = gray_decode g in
+    Printf.printf "%2d : %s => %s => %s : %2d\n" i (s i) (s g) (s b) b
+  done