/****************************************************************************** * Compilation: javac GrayCodeArray.java * Execution: java GrayCodeArray n * * Print the n-bit binary reflected Gray code use a pair of mutually * recursive functions and an array. * * % java GrayCodeArray 3 * 000 * 001 * 011 * 010 * 110 * 111 * 101 * 100 * ******************************************************************************/ public class GrayCodeArray { public static void show(boolean[] a) { for (int i = 1; i < a.length; i++) if (a[i]) StdOut.print(1); else StdOut.print(0); StdOut.println(); } public static void yarg(int n, boolean[] a) { if (n == 0) show(a); else { a[n] = true; gray(n-1, a); a[n] = false; yarg(n-1, a); } } public static void gray(int n, boolean[] a) { if (n == 0) show(a); else { a[n] = false; gray(n-1, a); a[n] = true; yarg(n-1, a); } } public static void main(String[] args) { int n = Integer.parseInt(args[0]); boolean[] a = new boolean[n+1]; gray(n, a); } }