The best method for counting bits in a 32-bit integer（2） 

long count_bits(long n) {     
  unsigned int c; // c accumulates the total bits set in v
  for (c = 0; n; c++) 
    n &= n - 1; // clear the least significant bit set
  return c;
}


http://gurmeetsingh.wordpress.com/2008/08/05/fast-bit-counting-routines/
posted @ 2010-03-13 23:19  octoberfirst  阅读(171)  评论(0)  编辑  收藏  举报