Count 1 in bits ref: http://qiita.com/giwa/items/f4517e23570e99742083

file0.txt

Which means if x = 10101001010100
                              ^
                              |
                              |
                              |

                       First set bit from the end

file1.cpp

#include<iostream>
#include<bitset>

using namespace std;

int main(){
    // 11111 in bits
    unsigned int x = 15;

    int total = 0;

    while (x != 0){
        cout << x << endl;
        bitset<32> a1(x);
        cout << a1 << endl;
        bitset<32> a2(x - 1);
        cout << a2 << endl;

        x = x & (x - 1);
        total++;

        bitset<32> a3(x);
        cout << a3 << endl;

    }

    cout << total << endl;

}

file2.txt

15
// x
00000000000000000000000000001111
// x - 1
00000000000000000000000000001110
// x & (x - 1)
00000000000000000000000000001110
14
// x
00000000000000000000000000001110
// x - 1
00000000000000000000000000001101
// x & (x -1)
00000000000000000000000000001100
12
// x 
00000000000000000000000000001100
// x - 1
00000000000000000000000000001011
// x & (x - 1)
00000000000000000000000000001000
8
// x
00000000000000000000000000001000
// x - 1
00000000000000000000000000000111
// x & (x - 1)
00000000000000000000000000000000
4