//  统计一个数二进制中的1的个数

#include <stdio.h>

int count(int a)

{

	int count = 0;

	while (a)

	{

		count++;

		a = a & (a - 1);

	}

	return count;

}

int main()

{

	printf("%d\n", count(10));

	printf("%d\n", count(0));

	printf("%d\n", count(-1));

	return 0;

}