Node JS function that takes an unsigned integer and returns wrong number of '1' bits

Issue

This Node JS function takes input as signed 2's complement and any particular reason why it returns wrong number of '1' bits Explanation: The input binary string 11111111111111111111111111111101 has a total of thirty one '1' bits.

Here is function which should return the output as 31 whereas it returns 1

            var hammingWeight = function(n) {
                let count = 0;
                while (n !== 0) {
                  n = n & (n - 1);
                  count++;
                }
              
                return count;
              };

            console.log(hammingWeight(11111111111111111111111111111101))

Here is console output

            PS C:\VSB-PRO> node Fibo.js
            1

any reason what could have gone wrong in the javascript code,your help is highly appreciated

Regards,

Carolyn

Solution

When you call hammingWeight(101), you are not using the binary string 101₂ (4+1 = 5), but the decimal number 101₁₀ (one hundred and one). Try instead hammingWeight(0b101).

Answered By - jtbandes