求二进制数中1的个数（编程之美2.1）

#include "stdafx.h"

int count(int t)
{
	int ret = 0;
	while(t)
	{
		t &= t-1;
		ret++;
	}
	return ret;
}

int _tmain(int argc, _TCHAR* argv[])
{
	printf("%d\n",count(1));
	printf("%d\n",count(2));
	printf("%d\n",count(7));
	return 0;
}