How to swap the two consecutive bits of unsigned integer ?

844 views

posted Nov 4, 2013 by Anuj Yadav

Share this question

swap is needed only if nth and nth bit are different ie 01 or 10.

commented Nov 5, 2013 by Salil Agrawal

int main()
{
  unsigned int N,Mask1,Mask2,Mask3,T1,T2,T3,k;
  scanf("%u",&N);
  scanf("%u",&k);
  /* 1's in bit 0 and bit 1 position */
  Mask1=0x0003;
  /* 1's in positions k and k+1 and 0's else where */
  Mask2=Mask1<<k;
  /* 0's in positions k and k+1 and 1's else where */
  Mask3=~Mask2;
  /* bring bits at position k and k+1 to bit 0 and bit 1 position*/
  T1=(N&Mask2)>>k;
  if(T1!=0&&T1!=3)
  {
    T1=T1^Mask1; /* swap */
    T1=T1<<k; /* shift the swapped bits to original position*/
    T2=N&Mask3;
    /* append other bits(0 to k-1 and k+2 to 15) */
    T3=T2|T1;
    printf("%u",T3);
  }
  else
    printf("%u",N);
}

commented Nov 6, 2013 by anonymous

unsigned char t1,t2;
t1=c&0*0F;
t2=c&0*F0;
t1=t1<<4;
t2=t2>>4;
return (t2|t1);

commented Nov 7, 2013 by anonymous

1 Answer

Try this to swap all consecutive bits

For 8 bit integer

u_int8 swap_bits(u_int8 ch)
{
    return ((ch & 0xAA)>>;1 ) | ( (ch & 0x55) << 1);
}

For 16 bit integer

u_int16 swap_bits(u_int16 ch)
{
    return ((ch & 0xAAAA)>>;1 ) | ( (ch & 0x5555) << 1);
}

answer Nov 5, 2013 by anonymous

...

How to swap the two consecutive bits of unsigned integer ?

Your comment on this post:

1 Answer

Your comment on this answer:

Your answer

Preview