std::countl_zero(3)

💅 std::countl_zero 💅

okay bestie, this one is from the C++ Standard Libary manual — yes, that spelling is literally on the page, don't come for me 😭. It's giving bit-counting main character energy, and it's here to count leading zeros for you, no cap 💖.

🎀 NAME 🎀

std::countl_zero - std::countl_zero

✨ Synopsis ✨

First up, the official setup:

Defined in header <bit>
template< class T >                         (since C++20)
constexpr int countl_zero( T x ) noexcept;

It returns the number of consecutive 0 bits in the value of x, starting from the most significant bit — that's the "left" side, iykyk 👑.

This overload participates in overload resolution only if T is an unsigned integer type (that is, unsigned char, unsigned short, unsigned int, unsigned long, unsigned long long, or an extended unsigned integer type). Periodt.

🌸 Parameters 🌸

• x — value of unsigned integer type 🫶

🦋 Return value 🦋

The number of consecutive 0 bits in the value of x, starting from the most significant bit. Literally the whole vibe. ✨

⭐ Notes ⭐

Feature-test macro check, bestie:

• __cpp_lib_bitops — value 201907L, std (C++20), feature Bit operations 🌈

🔥 Example 🔥

This example is serving 8-bit realness — run it and see:

       // Run this code

        #include <bit>
        #include <bitset>
        #include <cstdint>
        #include <iostream>

        int main()
        {
            for (const std::uint8_t i : {0, 0b11111111, 0b11110000,
       0b00011110})
                std::cout << "countl_zero( " << std::bitset<8>(i) << " ) = "
                          << std::countl_zero(i) << '\n';
        }

🍓 Output 🍓

countl_zero( 00000000 ) = 8
countl_zero( 11111111 ) = 0
countl_zero( 11110000 ) = 0
countl_zero( 00011110 ) = 3

👑 See also 👑

• countl_one (C++20) — counts the number of consecutive 1 bits, starting from the most significant bit (function template) 🔥
• countr_zero (C++20) — counts the number of consecutive 0 bits, starting from the least significant bit (function template) 💜
• countr_one (C++20) — counts the number of consecutive 1 bits, starting from the least significant bit (function template) 🌸
• popcount (C++20) — counts the number of 1 bits in an unsigned integer (function template) ⭐
• all, any, none — checks if all, any or none of the bits are set to true (public member function of std::bitset<N>) 🦋

That's the tea from http://cppreference.com, version date 2024.06.10, page std::countl_zero(3) — bye bestie, slay your bit ops 💅✨