/*
  Name:    ex20-7.c
  Purpose: Practice with "bit fiddling"
  Author:  The rotate functions given here were provided by W.W. Norton & Co.;
           the main() function written by Bill Slough
*/
#include <stdio.h>

#define HIGH_BIT (~(~0U >> 1))
#define LOW_BIT  1
#define NBITS 32

/* rotate the quantity i by n bit positions to the left */
unsigned int rotate_left(unsigned int i, int n)
{
  while (n-- > 0)
    i = (i << 1) | (i & HIGH_BIT ? LOW_BIT : 0);
  return i;
}

/* rotate the quantity i by n bit positions to the right */
unsigned int rotate_right(unsigned int i, int n)
{
  while (n-- > 0)
    i = (i >> 1) | (i & LOW_BIT ? HIGH_BIT : 0);
  return i;
}

int main(void) {
    /* a simple test driver/demo for the rotate functions */
    unsigned int myValue = 0x12345678;
    int n;

    /* test the left rotations */
    printf("Left rotations:\n");
    for (n = 0; n <= NBITS; n++)
        printf("...by %2d positions: %8.8x\n", n, rotate_left(myValue, n));

    /* test the right rotations */
    printf("\nRight rotations:\n");
    for (n = 0; n <= NBITS; n++)
        printf("...by %2d positions: %8.8x\n", n, rotate_right(myValue, n));

    return 0;
}