Number 1 bits

number1bits_fcodelab.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace number1bits_fCodeLab
{
    class Program
    {
        /*
         * Write a function that takes an unsigned integer and returns the number of 1 bits it has.

Example:

The 32-bit integer 11 has binary representation

00000000000000000000000000001011
so the function should return 3.

Note that since Java does not have unsigned int, use long for Java
         */
        static void Main(string[] args)
        {
        }

        public class Solution
        {
            public int numSetBits(long a)
            {
                int count = 0;
                while (a > 0)
                {
                    long leastSignificantBit = a & 1;
                    if (leastSignificantBit == 1)
                        count++;
                    a = a >> 1;   // bug001 - writing, forget "a =" in first writing, need compiler's help
                }
                return count;
            }
        }

    }
}