Amazon Interview Question: How do you check if the 5th b... | Glassdoor

Interview Question

Software Developer Engineer Intern Interview

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


Interview Answer

1 Answer


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

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