Google Interview Question: Count the number of bits set ... | Glassdoor.co.uk

## Interview Question

Software Engineering Intern Interview London, England

# Count the number of bits set in an integer. What is your

favorite language and what you don't like about that language.

0

This question totally caught me off guard because I haven't dealt anything about bit manipulation before

Interview Candidate on 31 Mar 2014
0

&gt;Count the number of bits set in an integer
I assume that this questrion suppose to count 1's (1 = bit is set(or enabled))
1 - enter an integer (for example 2)
2 - put binary form of 2 into a string and count 1's
(in C++ you can use a bitset and it's method called count:
...
bitset x(number);
cout &lt;&lt; x.count(); //count number of 1's (bits which set)
...

Andrey on 6 Jun 2014
3

The interviewer probably wanted you to use bit-wise operations. In java you would bit-wise "and" the number with
1 left-shifted by a number i from 0 to 31. This would return zero if the i-th bit is not set, or something other than zero otherwise.

public int getBits(int n)
{
int count=0;
for(int i=0;i&lt;31;i++)//bit which we are checking
{
if(n &amp; (1&lt;

Lenny on 10 Sep 2014