Rotates unsigned int by a specified number of bits - C Operator

C examples for Operator:Bit Operator

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Description

Rotates unsigned int by a specified number of bits

Demo Code

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

#define CLEARINPUT while (getchar() != '\n') continue

unsigned int rotate_l(unsigned int value, int n);

const unsigned int BITS = sizeof(unsigned int) * CHAR_BIT;
const unsigned int LBITMASK = 1 << (BITS - 1);

int main(void){
  unsigned int value, rotated;
  int n;//from www  .  ja  v  a2  s.  c om

  printf("Enter a non-negative integer value: ");
  while (scanf("%u", &value) == 1)
  {
    printf("Enter a number of positions to rotate: ");
    while (scanf("%d", &n) == 1)
    {
      puts("Before rotation:");
      for (int i = 0; i < BITS; i++)
      {
        if ((value << i) & LBITMASK)
          putchar('1');
        else
          putchar('0');
      }
      putchar('\n');
      printf("After rotation by %d positions:\n", n);
      rotated = rotate_l(value, n);
      for (int i = 0; i < BITS; i++)
      {
        if ((rotated << i) & LBITMASK)
          putchar('1');
        else
          putchar('0');
      }
      putchar('\n');
      printf("Enter a number of positions to rotate: ");
    }
    CLEARINPUT;
    printf("\nEnter a non-negative integer value: ");
  }

  puts("Bye.");
  return 0;

}
// rotate the bits in value n postitions to the left
unsigned int rotate_l(unsigned int value, int n){
  int leftbit;

  for (int i = 0; i < n; i++){
    leftbit = value & LBITMASK;
    value <<= 1;
    if (leftbit)
      value |= 1;
  }

  return value;
}

Result


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