Count how many 1 in binary representation of a 32-bit integer.

public class Solution {
    /**
     * @param num: an integer
     * @return: an integer, the number of ones in num
     */
    public int countOnes(int num) {
        // write your code here
        int count = 0;
        for (int i = 0; i < 32; i++) {
            if((num & 1) == 1) count ++;
            num >>= 1
        }
        return count;
    }
}

class Solution:
    """
    @param: num: An integer
    @return: An integer
    """
    def countOnes(self, num):
        # write your code here
        count = 0
        for _ in xrange(32):
            if num & 1 == 1:
                count += 1
            num >>= 1
        return count