Amazon.com

  www.amazon.com
  www.amazon.com

Interview Question

Software Developer Engineer Intern Interview

How do you check if the 5th bit is a 1 in a binary number

Answer

Interview Answer

1 Answer

3

We can use a mask: 16 is represented in binary as 100000 (with the 5th bit set to 1).

To the check if the 5th bit is one, we just need to do a bit-wise and of the number with the mask:

if (x & 16 > 0) {
    // the 5th bit is one
}

For a more general case, to know if the k th bit is set to 1, we can shift the bit:
if ((x >> (k - 1)) & 1 > 0) {
    // the kth bit is one
}

Anonymous on Jul 30, 2013

Add Answers or Comments

To comment on this, Sign In or Sign Up.