c - K&R 2-8 rightrotate (length of integer in bits) -

write function rightrot(x,n) returns value of integer x rotated right n operations

i can't see how can bits , put them in right position without requiring length of x(the amount of bits).

am thinking wrong or need length of x somehow? if so, how go getting length of x?

the code below wrong probaply way, put length_x in demonstrate problem.
i hope can point me in right direction.

#include <stdio.h>  unsigned rightrot(unsigned x, int n);  main() {     unsigned x = 75;     int p, n, y;     p = 5;     n = 3;     y = 45;      printf("%u\n",rightrot(x,n)); }    unsigned rightrot(unsigned x, int n) {      oldn = (x & ~(~0 << n)) << length_x;      x = x >> n | oldn;     return x;  } 

try:

unsigned int rrot(unsigned int x, int n) {      int len;      (len=31;len>=0 && !((1 << len) & x);len--);      len++;       return ((x >> n) | (x << (len - n)) & ((1 << len) - 1); } 

the loop should find length in bits of x. iterates along bits of n, checking if bit high; if so, length of number.

note: no checks made len greater n.