Book of programming problems

Complexity (1-100): 27

Grey code is a code Grey(x) such that each succeeding code Grey(x-1) differs from its predecessors in one bit. Example:

x	Grey(x)
0000 0001 0010 0011 0100 0101 0110 0111	0000 0001 0011 0010 0110 0111 0101 0100

There are more than one codes which hold this property. The task is to find such function Grey(x), which will map any integer number in the range 0..2³¹-1 to its Grey code.

It may be noted that the code Grey(x) = x xor (x>>1), where x >> 1 is a right-shift by one bit.