一个正整数int有多少bit位为一

public static int bitCount(int x) {
int count  = 0;
while(x > 0) {
count += (x % 2);
x = x / 2;
}
return count;
}

public static int bitCount(int x) {
int count  = 0;
while(x > 0) {
// 可以去掉最右那个为1的bit位
x = x & (x-1);
count++;
}
return count;
}