Data commit

Task/Gray-code/Tcl/gray-code-1.tcl

@@ -0,0 +1,14 @@
+namespace eval gray {
+    proc encode n {
+	expr {$n ^ $n >> 1}
+    }
+    proc decode n {
+	# Compute some bit at least as large as MSB
+	set i [expr {2**int(ceil(log($n+1)/log(2)))}]
+	set b [set bprev [expr {$n & $i}]]
+	while {[set i [expr {$i >> 1}]]} {
+	    set b [expr {$b | [set bprev [expr {$n & $i ^ $bprev >> 1}]]}]
+	}
+	return $b
+    }
+}

Task/Gray-code/Tcl/gray-code-2.tcl

@@ -0,0 +1,6 @@
+package require Tcl 8.6; # Just for %b format specifier
+for {set i 0} {$i < 32} {incr i} {
+    set g [gray::encode $i]
+    set b [gray::decode $g]
+    puts [format "%2d: %05b => %05b => %05b : %2d" $i $i $g $b $b]
+}