tcpl_ex-2-8.c

/*
 * Exercise 2-8. Write a function rightrot(x,n) that returns the value of the
 * integer x rotated to the right by n positions.
 */
#include <stdio.h>

unsigned int rightrot(unsigned int x, int n);

unsigned int rightrot(unsigned int x, int n) {
	while (n > 0) {
		if ((x & 1) == 1)
			x = (x >> 1) | ~(~0u >> 1);
		else 
			x = x >> 1;
		n--;
	}
	return x;
}

int main(void)
{
	unsigned int x = 0x000000f8;
	unsigned int r = 0xc0000007;
	int n = 5;
	if (r == rightrot(x, n))
		printf("assert sucessful!\n");
	else
		printf("assert fail!\n");

	return 0;
}