[题]写一个函数返回参数二进制中1的个数。

int main()
{
  int num = 0;
  int count = 0;
  scanf("%d", &num);
  while (num)
  {
    if (num % 2 == 1)
    {
      count++;
    }
    num /= 2;
  }
  printf("%d\n", count);
  return 0;
}

int main()
{
  int num = 0;
  scanf("%d", &num);
  int i = 0;
  int count = 0;
  for (i = 0; i <=32;i++)
  {
    if ((num >> i) & 1 == 1)
      count++;
  }
  printf("%d\n", count);
  return 0;
}

int main()
{
  int n = 0;
  scanf("%d", &n);
  int count = 0;
  while (n)
  {
    if (n)
    {
      count++;
    }
    n = n & (n - 1);
  }
  printf("%d\n", count);
  return 0;
}