Count number of 1's in a Number

Count the number of 1's in a number's representation.
E.g. Number 23 is 0001 0111
So there are 4 One's

Approach
Left Shift a number (equivalent to dividing by 2). Then if divided number is a double of original number, ignore. Else increment count (the original number is odd).
23 >> 1   gives 11
11 >> 1   gives 5
5  >> 1    gives 2
2 >> 1     gives 1

Solution