func bin2gray(n) {
    n ^ (n >> 1);
}

func gray2bin(num) {
    var bin = num;
    while (num >>= 1) { bin ^= num };
    return bin;
}

0..31 -> each { |i|
    var gr = bin2gray(i);
    printf("%d\t%b\t%b\t%b\n", i, i, gr, gray2bin(gr));
}