std::bitset::operator>,>>=(3)

💅 std::bitset::operator>,>>=(3)

okay bestie so this is a page from the C++ Standard Libary man pages (yes, that's how it's spelled on the tin, don't come for me 🫶) and it's all about shifting bits around in a std::bitset. Section three of the manual, periodt. ⭐

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✨ NAME ✨

std::bitset::operator>,>>= — literally std::bitset::operator>,>>=, that's the whole name, no notes 💀

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🌸 Synopsis 🌸

bitset operator<<( std::size_t pos ) const; (1) (noexcept since C++11)
                                                    (constexpr since C++23)
bitset& operator<<=( std::size_t pos );     (2) (noexcept since C++11)
                                                    (constexpr since C++23)
bitset operator>>( std::size_t pos ) const; (3) (noexcept since C++11)
                                                    (constexpr since C++23)
bitset& operator>>=( std::size_t pos );     (4) (noexcept since C++11)
                                                    (constexpr since C++23)

So what's the vibe? This family performs a binary shift left (towards higher index positions) and a binary shift right (towards lower index positions). Zeroes get shifted in, and any bits that would land on an index out of range are just dropped — ignored, gone, not invited to the party 🙈.

1. , 2. — these two do the binary shift left. The (2) version is destructive, iykyk: it performs the shift directly on the current object, no new object for you 💅
2. , 4. — these two do the binary shift right. The (4) version is destructive too, i.e. it performs the shift to the current object.

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🎀 Parameters 🎀

• pos — number of positions to shift the bits 🌈

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👑 Return value 👑

1. , 3. — a new bitset object containing the shifted bits ✨
2. , 4. — *this 🫶

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🦋 Example 🦋

// Run this code

#include <bitset>
#include <iostream>

int main()
{
    std::bitset<8> b{0b01110010};
    std::cout << b << " (initial value)\n";

    for (; b.any(); b >>= 1)
    {
        while (!b.test(0))
            b >>= 1;
        std::cout << b << '\n';
    }

    std::cout << b << " (final value)\n";
}

💖 Output:

01110010 (initial value)
00111001
00000111
00000011
00000001
00000000 (final value)

like, the way it just eats its own trailing zeroes one shift at a time? obsessed 😭🔥

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🌈 See also 🌈

• rotl — computes the result of bitwise left-rotation (C++20) (function template) ⭐
• rotr — computes the result of bitwise right-rotation (C++20) (function template) ⭐
• operator&= — performs binary AND, OR, XOR and NOT (public member function) 💜
• operator|= — performs binary AND, OR, XOR and NOT (public member function) 💜
• operator^= — performs binary AND, OR, XOR and NOT (public member function) 💜
• operator~ — performs binary AND, OR, XOR and NOT (public member function) 💜

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ngl bestie, if you're shifting by an amount that sends bits out of range, they're just gone — dropped, ignored, no cap. that's the documented behaviour, not a bug, so don't @ me 💀

okay that's the whole page, go shift some bits and slay 💅✨

— sourced from http://cppreference.com, version 2024.06.10. bye bestie, mwah 🎀💖🦋