How do I count the number of zero bits in an integer?

Question

How would i go about finding the number of \'zero\' bits in C++. Suppose I have an integer;

int value = 276; 

For which I have the bits 100010

Answer 1

If you use GCC, you can try built-in functions:

int __builtin_popcount (unsigned int x) 
int __builtin_ctz (unsigned int x)
int __builtin_clz (unsigned int x)

See GCC Documentation for details.