/*
 * gray_code.c
 *
 * Author: Matt Dorsett
 *
 * This program calculates gray codes for [0,15] and prints out the absolute difference
 * between each successive code. Notice that the differences are all powers of 2 (i.e.
 * just one bit is changing). 
 */

#include <stdio.h>

int calc_gray_code(int n);

int main(int argc, char **argv)
{
    int old_g = 0;
    int new_g = 0;
    for (int i = 0; i < 16; i++)
    {
        new_g = calc_gray_code(i);
        int diff = old_g > new_g ? old_g - new_g : new_g - old_g;
        printf("Gray code of 0x%X is 0x%X, absolute difference is %d\n", i, new_g, diff);
        old_g = new_g;
    }
}

/* Returns the gray encoding of n */
int calc_gray_code(int n)
{
    return (n >> 1) ^ n;
}