Exercise 2.08

Page 49

Write a function rightrot(x,n) that returns the value of the integer x rotated to the right by n bit positions.

#include <limits.h>
#include <stdio.h>

unsigned rightrot(unsigned x, int n);
void print_bits(unsigned x);
unsigned get_leftmost_bit(unsigned x);

int main()
{
	print_bits(rightrot(0b01000111, 3));
}

unsigned rightrot(unsigned x, int n)
{
	return (x >> n) | ((x & ~(~0 << n)) << (sizeof(x) * CHAR_BIT - n));
}

void print_bits(unsigned x)
{
	for (unsigned i = 1 << (sizeof(x) * CHAR_BIT - 1); i > 0; i >>= 1) {
		if (i & x) {
			putchar('1');
		} else {
			putchar('0');
		}
	}
}