Description:

• This function counts the number of 1 bits (set bits) in an integer.

Syntax:

int __builtin_popcount(unsigned int x);

Example:

#include <iostream>

int main() {
    unsigned int x = 29; // Binary: 00011101
    int count = __builtin_popcount(x);
    std::cout << "Number of 1 bits in " << x << " is " << count << std::endl; // Output: 4

    return 0;
}