AI solution for JavaScript Coding Question on BFE.dev
96. count "1" in binary form

One approach would be to use bitwise operators. We can use the bitwise AND operator (&) to check whether a particular bit in the binary number is set to 1. We can do this by ANDing the number with a mask, which has only one bit set to 1 at a time, and then shifting the mask to the left one bit at a time until we have checked all the bits in the number.

Here's an example implementation:

function countOne(num) {
  let count = 0;
  while (num > 0) {
    if (num & 1) {
      count++;
    }
    num >>= 1;
  }
  return count;
}

In this implementation, we start by initializing a count variable to 0. We then enter a loop that continues as long as the number num is greater than 0.

In each iteration of the loop, we check whether the least significant bit of num is 1 by ANDing it with 1. If the result is 1, then we increment the count variable.

We then shift the number num one bit to the right, which has the effect of dropping the least significant bit and shifting all the remaining bits to the right.

By repeating this process, we check each bit in the number and count the ones. Finally, we return the count.