191. Number of 1 Bits

Write a function that takes an unsigned integer and returns the number of ’1’ bits it has (also known as the Hamming weight).

For example, the 32-bit integer ’11’ has binary representation 00000000000000000000000000001011, so the function should return 3.

class Solution {
public:
int hammingWeight(uint32_t n)
{
int count = 0;
while(n)
{
++ count;
n = n & (n - 1);

}
return count;
}
};