[刷题]Count 1 in Binary

[LIntCode]Count 1 in Binary

public class Solution {
    /**
     * @param num: an integer
     * @return: an integer, the number of ones in num
     */
    public int countOnes(int num) {
        // 2015-07-17
        if (num <= 0) {
            return 0;
        }
        int tmp = num;
        int count = 0;
        while(tmp > 0) {
            if (tmp % 2 == 1) {
                count++;
            }
            tmp /= 2;
        }
        return count;
    }
};