__builtin_popcount

__builtin_popcount is a built-in function in C++ that counts the number of set bits (bits with a value of 1) in an integer. Here is an explanation of each step involved in using __builtin_popcount:

1. Include the necessary header file: Before using __builtin_popcount, make sure to include the header file, which provides the necessary definitions for integer types.

2. Use __builtin_popcount function: To count the number of set bits in an integer, simply call the __builtin_popcount function and pass the integer as an argument. The function returns the count of set bits as an integer value.

3. Example usage: Here is an example of how to use __builtin_popcount:

#include <cstdint>

int main() {
    uint32_t number = 5;  // binary: 101
    int count = __builtin_popcount(number);

    // Output the count of set bits
    std::cout << "Number of set bits: " << count << std::endl;

    return 0;
}

In this example, the variable number is set to 5, which in binary representation is 101. The __builtin_popcount function is called with number as the argument, and its return value is stored in the variable count. The output will be "Number of set bits: 2".

That's it! This is a brief explanation of how to use __builtin_popcount in C++ to count the number of set bits in an integer. Let me know if you have any further questions.